Vomiting
Overview
 
Vomiting is the forceful expulsion of the contents of one's stomach
Stomach
The stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is...

 through the mouth
Mouth
The mouth is the first portion of the alimentary canal that receives food andsaliva. The oral mucosa is the mucous membrane epithelium lining the inside of the mouth....

 and sometimes the nose
Human nose
The visible part of the human nose is the protruding part of the face that bears the nostrils. The shape of the nose is determined by the ethmoid bone and the nasal septum, which consists mostly of cartilage and which separates the nostrils...

. Vomiting can occur due to a wide variety of conditions; it may present as a specific response to ailments like gastritis
Gastritis
Gastritis is an inflammation of the lining of the stomach, and has many possible causes. The main acute causes are excessive alcohol consumption or prolonged use of nonsteroidal anti-inflammatory drugs such as aspirin or ibuprofen. Sometimes gastritis develops after major surgery, traumatic...

 or poison
Poison
In the context of biology, poisons are substances that can cause disturbances to organisms, usually by chemical reaction or other activity on the molecular scale, when a sufficient quantity is absorbed by an organism....

ing, or as a non-specific sequela
Sequela
A sequela) is a pathological condition resulting from a disease, injury, or other trauma.Chronic kidney disease, for example, is sometimes a sequela of diabetes, and neck pain is a common sequela of whiplash or other trauma to the cervical vertebrae. Post-traumatic stress disorder may be a...

 of disorders ranging from brain tumor
Brain tumor
A brain tumor is an intracranial solid neoplasm, a tumor within the brain or the central spinal canal.Brain tumors include all tumors inside the cranium or in the central spinal canal...

s and elevated intracranial pressure
Intracranial pressure
Intracranial pressure is the pressure inside the skull and thus in the brain tissue and cerebrospinal fluid . The body has various mechanisms by which it keeps the ICP stable, with CSF pressures varying by about 1 mmHg in normal adults through shifts in production and absorption of CSF...

 to overexposure to ionizing radiation
Ionizing radiation
Ionizing radiation is radiation composed of particles that individually have sufficient energy to remove an electron from an atom or molecule. This ionization produces free radicals, which are atoms or molecules containing unpaired electrons...

. The feeling that one is about to vomit is called nausea
Nausea
Nausea , is a sensation of unease and discomfort in the upper stomach with an involuntary urge to vomit. It often, but not always, precedes vomiting...

, which usually precedes, but does not always lead to, vomiting.
Quotations

You know in some cultures, they only eat vomit. I never been there before, but I read about it... IN A BOOK! :— Ben Stiller in Dodgeball: A True Underdog Story

Encyclopedia
Vomiting is the forceful expulsion of the contents of one's stomach
Stomach
The stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is...

 through the mouth
Mouth
The mouth is the first portion of the alimentary canal that receives food andsaliva. The oral mucosa is the mucous membrane epithelium lining the inside of the mouth....

 and sometimes the nose
Human nose
The visible part of the human nose is the protruding part of the face that bears the nostrils. The shape of the nose is determined by the ethmoid bone and the nasal septum, which consists mostly of cartilage and which separates the nostrils...

. Vomiting can occur due to a wide variety of conditions; it may present as a specific response to ailments like gastritis
Gastritis
Gastritis is an inflammation of the lining of the stomach, and has many possible causes. The main acute causes are excessive alcohol consumption or prolonged use of nonsteroidal anti-inflammatory drugs such as aspirin or ibuprofen. Sometimes gastritis develops after major surgery, traumatic...

 or poison
Poison
In the context of biology, poisons are substances that can cause disturbances to organisms, usually by chemical reaction or other activity on the molecular scale, when a sufficient quantity is absorbed by an organism....

ing, or as a non-specific sequela
Sequela
A sequela) is a pathological condition resulting from a disease, injury, or other trauma.Chronic kidney disease, for example, is sometimes a sequela of diabetes, and neck pain is a common sequela of whiplash or other trauma to the cervical vertebrae. Post-traumatic stress disorder may be a...

 of disorders ranging from brain tumor
Brain tumor
A brain tumor is an intracranial solid neoplasm, a tumor within the brain or the central spinal canal.Brain tumors include all tumors inside the cranium or in the central spinal canal...

s and elevated intracranial pressure
Intracranial pressure
Intracranial pressure is the pressure inside the skull and thus in the brain tissue and cerebrospinal fluid . The body has various mechanisms by which it keeps the ICP stable, with CSF pressures varying by about 1 mmHg in normal adults through shifts in production and absorption of CSF...

 to overexposure to ionizing radiation
Ionizing radiation
Ionizing radiation is radiation composed of particles that individually have sufficient energy to remove an electron from an atom or molecule. This ionization produces free radicals, which are atoms or molecules containing unpaired electrons...

. The feeling that one is about to vomit is called nausea
Nausea
Nausea , is a sensation of unease and discomfort in the upper stomach with an involuntary urge to vomit. It often, but not always, precedes vomiting...

, which usually precedes, but does not always lead to, vomiting. Antiemetic
Antiemetic
An antiemetic is a drug that is effective against vomiting and nausea. Antiemetics are typically used to treat motion sickness and the side effects of opioid analgesics, general anaesthetics, and chemotherapy directed against cancer....

s are sometimes necessary to suppress nausea and vomiting. In severe cases, where dehydration
Dehydration
In physiology and medicine, dehydration is defined as the excessive loss of body fluid. It is literally the removal of water from an object; however, in physiological terms, it entails a deficiency of fluid within an organism...

 develops, intravenous fluid may be required.

Vomiting is different from regurgitation
Regurgitation (digestion)
Regurgitation is the expulsion of material from the mouth, pharynx, or esophagus, usually characterized by the presence of undigested food or blood.Regurgitation is used by a number of species to feed their young...

, although the two terms are often used interchangeably. Regurgitation is the return of undigested food back up the esophagus
Esophagus
The esophagus is an organ in vertebrates which consists of a muscular tube through which food passes from the pharynx to the stomach. During swallowing, food passes from the mouth through the pharynx into the esophagus and travels via peristalsis to the stomach...

 to the mouth
Mouth
The mouth is the first portion of the alimentary canal that receives food andsaliva. The oral mucosa is the mucous membrane epithelium lining the inside of the mouth....

, without the force and displeasure associated with vomiting. The causes of vomiting and regurgitation are generally different.

Aspiration of vomit

Vomiting can be dangerous if the gastric content gets into the respiratory tract. Under normal circumstances the gag reflex
Gag reflex
The pharyngeal reflex or gag reflex is a reflex contraction of the back of the throat, evoked by touching the soft palate or sometimes the back of the tongue. It prevents something from entering the throat except as part of normal swallowing and helps prevent choking...

 and coughing prevent this from occurring, however these protective reflexes are compromised in persons under the influences of certain substances such as alcohol
Ethanol
Ethanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug and one of the oldest recreational drugs. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a...

 or anesthesia
Anesthesia
Anesthesia, or anaesthesia , traditionally meant the condition of having sensation blocked or temporarily taken away...

. The individual may choke and asphyxiate or suffer an aspiration pneumonia
Aspiration pneumonia
Aspiration pneumonia is bronchopneumonia that develops due to the entrance of foreign materials into the bronchial tree, usually oral or gastric contents...

.

Dehydration and electrolyte imbalance

Prolonged and excessive vomiting depletes the body of water (dehydration), and may alter the electrolyte status. Gastric vomiting leads to the loss of acid (protons) and chlorine directly. Combined with the resulting alkaline tide
Alkaline tide
Alkaline tide refers to a condition, normally encountered after eating a meal, when stomach acid is released into the stomach causing a temporary increase in pH of the blood....

, this leads to hypochloremic
Hypochloremia
Hypochloremia is an electrolyte disturbance whereby there is an abnormally depleted level of the chloride ion in the blood.It rarely occurs in the absence of other abnormalities.It can be associated with hypoventilation....

 metabolic alkalosis
Metabolic alkalosis
Metabolic alkalosis is a metabolic condition in which the pH of tissue is elevated beyond the normal range . This is the result of decreased hydrogen ion concentration, leading to increased bicarbonate, or alternatively a direct result of increased bicarbonate concentrations.-Terminology:*Alkalosis...

 (low chloride
Chloride
The chloride ion is formed when the element chlorine, a halogen, picks up one electron to form an anion Cl−. The salts of hydrochloric acid HCl contain chloride ions and can also be called chlorides. The chloride ion, and its salts such as sodium chloride, are very soluble in water...

 levels together with high HCO3
Bicarbonate
In inorganic chemistry, bicarbonate is an intermediate form in the deprotonation of carbonic acid...

 and CO2 and increased blood pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...

) and often hypokalemia
Hypokalemia
Hypokalemia or hypokalaemia , also hypopotassemia or hypopotassaemia , refers to the condition in which the concentration of potassium in the blood is low...

 (potassium
Potassium
Potassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...

 depletion). The hypokalemia is an indirect result of the kidney
Kidney
The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...

 compensating for the loss of acid. With the loss of intake of food the individual may eventually become cachectic
Cachexia
Cachexia or wasting syndrome is loss of weight, muscle atrophy, fatigue, weakness, and significant loss of appetite in someone who is not actively trying to lose weight...

. A less frequent occurrence results from a vomiting of intestinal contents, including bile acids and HCO3-, which can lead to metabolic acidosis
Metabolic acidosis
In medicine, metabolic acidosis is a condition that occurs when the body produces too much acid or when the kidneys are not removing enough acid from the body. If unchecked, metabolic acidosis leads to acidemia, i.e., blood pH is low due to increased production of hydrogen by the body or the...

.

Mallory-Weiss tear

Repeated or profuse vomiting may cause erosions to the esophagus
Esophagus
The esophagus is an organ in vertebrates which consists of a muscular tube through which food passes from the pharynx to the stomach. During swallowing, food passes from the mouth through the pharynx into the esophagus and travels via peristalsis to the stomach...

 or small tears in the esophageal mucosa (Mallory-Weiss tear). This may become apparent if fresh red blood is mixed with vomit after several episodes.

Dentistry

Recurrent vomiting, such as observed in bulimia nervosa
Bulimia nervosa
Bulimia nervosa is an eating disorder characterized by binge eating and purging or consuming a large amount of food in a short amount of time, followed by an attempt to rid oneself of the food consumed, usually by purging and/or by laxative, diuretics or excessive exercise. Bulimia nervosa is...

, may lead to destruction of the tooth enamel
Tooth enamel
Tooth enamel, along with dentin, cementum, and dental pulp is one of the four major tissues that make up the tooth in vertebrates. It is the hardest and most highly mineralized substance in the human body. Tooth enamel is also found in the dermal denticles of sharks...

 due to the acidity of the vomit. Digestive enzymes can also have a negative effect on oral health, by degrading the tissue of the gums.

Pathophysiology

Receptors on the floor of the fourth ventricle
Fourth ventricle
The fourth ventricle is one of the four connected fluid-filled cavities within the human brain. These cavities, known collectively as the ventricular system, consist of the left and right lateral ventricles, the third ventricle, and the fourth ventricle...

 of the brain represent a chemoreceptor trigger zone
Chemoreceptor trigger zone
The chemoreceptor trigger zone , is an area of the medulla that receives inputs from blood-borne drugs or hormones, and communicates with the vomiting center, to initiate vomiting. The CTZ is close to the area postrema on the floor of the fourth ventricle and is outside of the blood-brain barrier...

, known as the area postrema
Area postrema
The area postrema is a medullary structure in the brain that controls vomiting. Its privileged location in the brain also allows the area postrema to play a vital role in the control of autonomic functions by the central nervous system.-Anatomy:...

, stimulation of which can lead to vomiting. The area postrema is a circumventricular organ and as such lies outside the blood-brain barrier
Blood-brain barrier
The blood–brain barrier is a separation of circulating blood and the brain extracellular fluid in the central nervous system . It occurs along all capillaries and consists of tight junctions around the capillaries that do not exist in normal circulation. Endothelial cells restrict the diffusion...

; it can therefore be stimulated by blood-borne drugs that can stimulate vomiting or inhibit it.

There are various sources of input to the vomiting center:
  • The chemoreceptor trigger zone at the base of the fourth ventricle has numerous dopamine D2 receptors, serotonin 5-HT3 receptors
    5-HT receptor
    The serotonin receptors, also known as 5-hydroxytryptamine receptors or 5-HT receptors, are a group of G protein-coupled receptors and ligand-gated ion channels found in the central and peripheral nervous systems. They mediate both excitatory and inhibitory neurotransmission...

    , opioid receptor
    Opioid receptor
    Opioid receptors are a group of G protein-coupled receptors with opioids as ligands. The endogenous opioids are dynorphins, enkephalins, endorphins, endomorphins and nociceptin. The opioid receptors are ~40% identical to somatostatin receptors...

    s, acetylcholine receptor
    Acetylcholine receptor
    An acetylcholine receptor is an integral membrane protein that responds to the binding of acetylcholine, a neurotransmitter.-Classification:...

    s, and receptors for substance P
    Substance P
    In the field of neuroscience, substance P is a neuropeptide: an undecapeptide that functions as a neurotransmitter and as a neuromodulator. It belongs to the tachykinin neuropeptide family. Substance P and its closely related neuropeptide neurokinin A are produced from a polyprotein precursor...

    . Stimulation of different receptors are involved in different pathways leading to emesis, in the final common pathway substance P appears involved.
  • The vestibular system
    Vestibular system
    The vestibular system, which contributes to balance in most mammals and to the sense of spatial orientation, is the sensory system that provides the leading contribution about movement and sense of balance. Together with the cochlea, a part of the auditory system, it constitutes the labyrinth of...

    , which sends information to the brain via cranial nerve VIII (vestibulocochlear nerve), plays a major role in motion sickness
    Motion sickness
    Motion sickness or kinetosis, also known as travel sickness, is a condition in which a disagreement exists between visually perceived movement and the vestibular system's sense of movement...

    , and is rich in muscarinic receptors
    Muscarinic acetylcholine receptor
    Muscarinic receptors, or mAChRs, are acetylcholine receptors that form G protein-coupled in the plasma membranes of certain neurons and other cells...

     and histamine H1 receptors
    Histamine receptor
    The histamine receptors are a class of G protein-coupled receptors with histamine as their endogenous ligand.There are four known histamine receptors:*H1 receptor*H2 receptor*H3 receptor*H4 receptor-Comparison:...

    .
  • The Cranial nerve X
    Vagus nerve
    The vagus nerve , also called pneumogastric nerve or cranial nerve X, is the tenth of twelve paired cranial nerves...

     (vagus nerve) is activated when the pharynx
    Pharynx
    The human pharynx is the part of the throat situated immediately posterior to the mouth and nasal cavity, and anterior to the esophagus and larynx. The human pharynx is conventionally divided into three sections: the nasopharynx , the oropharynx , and the laryngopharynx...

     is irritated, leading to a gag reflex.
  • The Vagal and enteric nervous system
    Enteric nervous system
    The enteric nervous system is a subdivision of the autonomic nervous system that directly controls the gastrointestinal system in vertebrates.It is derived from neural crest.-Function:...

     inputs transmit information regarding the state of the gastrointestinal system. Irritation of the GI mucosa by chemotherapy, radiation, distention, or acute infectious gastroenteritis
    Gastroenteritis
    Gastroenteritis is marked by severe inflammation of the gastrointestinal tract involving both the stomach and small intestine resulting in acute diarrhea and vomiting. It can be transferred by contact with contaminated food and water...

     activates the 5-HT3 receptors of these inputs.
  • The CNS
    Central nervous system
    The central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...

     mediates vomiting that arises from psychiatric disorders and stress from higher brain centers.


The vomiting act encompasses three types of outputs initiated by the chemoreceptor trigger zone: Motor, parasympathetic nervous system
Parasympathetic nervous system
The parasympathetic nervous system is one of the two main divisions of the autonomic nervous system . The ANS is responsible for regulation of internal organs and glands, which occurs unconsciously...

 (PNS), and sympathetic nervous system
Sympathetic nervous system
The sympathetic nervous system is one of the three parts of the autonomic nervous system, along with the enteric and parasympathetic systems. Its general action is to mobilize the body's nervous system fight-or-flight response...

 (SNS). They are as follows:
  • Increased saliva
    Saliva
    Saliva , referred to in various contexts as spit, spittle, drivel, drool, or slobber, is the watery substance produced in the mouths of humans and most other animals. Saliva is a component of oral fluid. In mammals, saliva is produced in and secreted from the three pairs of major salivary glands,...

    tion to protect tooth enamel
    Tooth enamel
    Tooth enamel, along with dentin, cementum, and dental pulp is one of the four major tissues that make up the tooth in vertebrates. It is the hardest and most highly mineralized substance in the human body. Tooth enamel is also found in the dermal denticles of sharks...

     from stomach acids. (Excessive vomiting leads to dental erosion
    Erosion (dental)
    Acid erosion, also known as dental erosion, is the irreversible loss of tooth structure due to chemical dissolution by acids not of bacterial origin. Dental erosion is the most common chronic disease of children ages 5–17, although it is only relatively recently that it has been recognised...

    ). This is part of the PNS output.
  • The body takes a deep breath to avoid aspirating
    Pulmonary aspiration
    Pulmonary aspiration is the entry of material from the oropharynx or gastrointestinal tract into the larynx and lower respiratory tract...

     vomit.
  • Retroperistalsis
    Retroperistalsis
    Retroperistalsis is the reverse of the involuntary smooth muscle contractions of peristalsis. It usually occurs as a precursor to vomiting. Local irritation of the stomach, such as bacteria or food poisoning, activates the emetic center of the brain which in turn signals an imminent vomiting reflex...

    , starts from the middle of the small intestine
    Small intestine
    The small intestine is the part of the gastrointestinal tract following the stomach and followed by the large intestine, and is where much of the digestion and absorption of food takes place. In invertebrates such as worms, the terms "gastrointestinal tract" and "large intestine" are often used to...

     and sweeps up digestive tract contents into the stomach, through the relaxed pyloric sphincter
    Pylorus
    The pylorus is the region of the stomach that connects to the duodenum . It is divided into two parts:* the pyloric antrum, which connects to the body of the stomach.* the pyloric canal, which connects to the duodenum....

    .
  • Intrathoracic pressure lowers (by inspiration
    Inhalation
    Inhalation is the movement of air from the external environment, through the air ways, and into the alveoli....

     against a closed glottis
    Glottis
    The glottis is defined as the combination of the vocal folds and the space in between the folds .-Function:...

    ), coupled with an increase in abdominal pressure as the abdominal muscles
    Abdomen
    In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...

     contract, propels stomach contents into the esophagus
    Esophagus
    The esophagus is an organ in vertebrates which consists of a muscular tube through which food passes from the pharynx to the stomach. During swallowing, food passes from the mouth through the pharynx into the esophagus and travels via peristalsis to the stomach...

     as the lower esophageal sphincter
    Cardia
    The cardia is the anatomical term for the part of the stomach attached to the esophagus. The cardia begins immediately distal to the z-line of the gastroesophageal junction, where the squamous epithelium of the esophagus gives way to the columnar epithelium of the gastrointestinal tract.Just...

     relaxes. The stomach itself does not contract in the process of vomiting except for at the angular notch
    Angular incisure
    Nearer the pyloric end of the stomach than its cardiac end is a well-marked notch, the angular incisure , which varies somewhat in position with the state of distension of the viscus....

    , nor is there any retroperistalsis in the esophagus.
  • Vomiting is ordinarily preceded by retching
    Retching
    Retching is a process in the human body where gastric contents are forced into the esophagus but do not enter the pharynx. Retching usually precedes vomiting, when the upper esophageal sphincter remains closed. If the upper esophageal sphincter is open, vomiting occurs. It can also be caused by a...

    .
  • Vomiting also initiates an SNS
    Sympathetic nervous system
    The sympathetic nervous system is one of the three parts of the autonomic nervous system, along with the enteric and parasympathetic systems. Its general action is to mobilize the body's nervous system fight-or-flight response...

     response causing both sweating and increased heart rate.


The neurotransmitter
Neurotransmitter
Neurotransmitters are endogenous chemicals that transmit signals from a neuron to a target cell across a synapse. Neurotransmitters are packaged into synaptic vesicles clustered beneath the membrane on the presynaptic side of a synapse, and are released into the synaptic cleft, where they bind to...

s that regulate vomiting are poorly understood, but inhibitors of dopamine
Dopamine
Dopamine is a catecholamine neurotransmitter present in a wide variety of animals, including both vertebrates and invertebrates. In the brain, this substituted phenethylamine functions as a neurotransmitter, activating the five known types of dopamine receptors—D1, D2, D3, D4, and D5—and their...

, histamine
Histamine
Histamine is an organic nitrogen compound involved in local immune responses as well as regulating physiological function in the gut and acting as a neurotransmitter. Histamine triggers the inflammatory response. As part of an immune response to foreign pathogens, histamine is produced by...

, and serotonin
Serotonin
Serotonin or 5-hydroxytryptamine is a monoamine neurotransmitter. Biochemically derived from tryptophan, serotonin is primarily found in the gastrointestinal tract, platelets, and in the central nervous system of animals including humans...

 are all used to suppress vomiting, suggesting that these play a role in the initiation or maintenance of a vomiting cycle. Vasopressin
Vasopressin
Arginine vasopressin , also known as vasopressin, argipressin or antidiuretic hormone , is a neurohypophysial hormone found in most mammals, including humans. Vasopressin is a peptide hormone that controls the reabsorption of molecules in the tubules of the kidneys by affecting the tissue's...

 and neurokinin may also participate.

Phases

The vomiting act has two phases. In the retching phase, the abdominal muscles undergo a few rounds of coordinated contractions together with the diaphragm and the muscles used in respiratory inspiration. For this reason, an individual may confuse this phase with an episode of violent hiccups. In this retching phase nothing has yet been expelled. In the next phase, also termed the expulsive phase, intense pressure is formed in the stomach brought about by enormous shifts in both the diaphragm and the abdomen. These shifts are, in essence, vigorous contractions of these muscles that last for extended periods of time - much longer than a normal period of muscular contraction. The pressure is then suddenly released when the upper esophageal sphincter relaxes resulting in the expulsion of gastric contents. For people not in the habit of exercising the abdominal muscles, they may be painful for the next few days. The relief of pressure and the release of endorphins into the bloodstream after the expulsion causes the vomiter to feel better.

Contents

Gastric secretions
Gastric acid
Gastric acid is a digestive fluid, formed in the stomach. It has a pH of 1 to 2 and is composed of hydrochloric acid , and large quantities of potassium chloride and sodium chloride...

 and likewise vomit are highly acid
Acid
An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...

ic. Recent food intake appears in the gastric vomit. Irrespective of the content, vomit tends to be malodorous
Odor
An odor or odour is caused by one or more volatilized chemical compounds, generally at a very low concentration, that humans or other animals perceive by the sense of olfaction. Odors are also commonly called scents, which can refer to both pleasant and unpleasant odors...

.

The content of the vomitus (vomit) may be of medical interest. Fresh blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....

 in the vomit is termed hematemesis
Hematemesis
Hematemesis or haematemesis is the vomiting of blood. The source is generally the upper gastrointestinal tract. Patients can easily confuse it with hemoptysis , although the latter is more common.-Signs:...

 ("blood vomiting"). Altered blood bears resemblance to coffee grounds (as the iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...

 in the blood is oxidized) and, when this matter is identified, the term "coffee ground vomiting
Coffee ground vomiting
Coffee ground vomitus refers to a particular appearance of vomit. Blood contains iron within heme molecules in red blood cells. When this iron has been exposed to gastric acid for some time, it becomes oxidized. This reaction causes the vomitus to look like ground coffee. Coffee-ground vomitus is...

" is used. Bile
Bile
Bile or gall is a bitter-tasting, dark green to yellowish brown fluid, produced by the liver of most vertebrates, that aids the process of digestion of lipids in the small intestine. In many species, bile is stored in the gallbladder and upon eating is discharged into the duodenum...

 can enter the vomit during subsequent heaves due to duodenal
Duodenum
The duodenum is the first section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear and the terms anterior intestine or proximal intestine may be used instead of duodenum...

 contraction if the vomiting is severe. Fecal vomiting is often a consequence of intestinal obstruction or a gastrocolic fistula
Fistula
In medicine, a fistula is an abnormal connection or passageway between two epithelium-lined organs or vessels that normally do not connect. It is generally a disease condition, but a fistula may be surgically created for therapeutic reasons.-Locations:Fistulas can develop in various parts of the...

 and is treated as a warning sign of this potentially serious problem ("signum mali ominis"); such vomiting is sometimes called "miserere."

If the vomiting reflex continues for an extended period with no appreciable vomitus, the condition is known as non-productive emesis or dry heaves, which can be painful and debilitating.

Color of vomit
  • Bright red in the vomit suggests bleeding from the esophagus
  • Dark red vomit with liver-like clots suggests profuse bleeding in the stomach, such as from a perforated ulcer
  • Coffee ground-like vomit suggests less severe bleeding in the stomach, because the gastric acid has had time to change the composition of the blood
  • Yellow vomit suggests bile. This indicates that the pyloric valve is open and bile is flowing into the stomach from the duodenum. (This is more common in older people.)

Differential diagnosis

Vomiting may be due to a large number of causes, and protracted vomiting has a long differential diagnosis
Differential diagnosis
A differential diagnosis is a systematic diagnostic method used to identify the presence of an entity where multiple alternatives are possible , and may also refer to any of the included candidate alternatives A differential diagnosis (sometimes abbreviated DDx, ddx, DD, D/Dx, or ΔΔ) is a...

.

Digestive tract

Causes in the digestive tract
  • Gastritis
    Gastritis
    Gastritis is an inflammation of the lining of the stomach, and has many possible causes. The main acute causes are excessive alcohol consumption or prolonged use of nonsteroidal anti-inflammatory drugs such as aspirin or ibuprofen. Sometimes gastritis develops after major surgery, traumatic...

     (inflammation of the gastric wall, usually by virus
    Virus
    A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...

    es)
  • Gastroenteritis
    Gastroenteritis
    Gastroenteritis is marked by severe inflammation of the gastrointestinal tract involving both the stomach and small intestine resulting in acute diarrhea and vomiting. It can be transferred by contact with contaminated food and water...

  • Pyloric stenosis
    Pyloric stenosis
    Pyloric stenosis is a condition that causes severe vomiting in the first few months of life. There is narrowing of the opening from the stomach to the intestines, due to enlargement of the muscle surrounding this opening , which spasms when the stomach empties...

     (in babies, this typically causes a very forceful "projectile vomiting" and is an indication for urgent surgery)
  • Bowel obstruction
    Bowel obstruction
    Bowel obstruction is a mechanical or functional obstruction of the intestines, preventing the normal transit of the products of digestion. It can occur at any level distal to the duodenum of the small intestine and is a medical emergency...

  • Overeating
    Overeating
    Overeating generally refers to the long-term consumption of excess food in relation to the energy that an organism expends , leading to weight gainingand often obesity. It may be regarded as an eating disorder....

  • Acute abdomen
    Acute abdomen
    The term acute abdomen refers to a sudden, severe abdominal pain of unclear etiology that is less than 24 hours in duration. It is in many cases a medical emergency, requiring urgent and specific diagnosis...

     and/or peritonitis
    Peritonitis
    Peritonitis is an inflammation of the peritoneum, the serous membrane that lines part of the abdominal cavity and viscera. Peritonitis may be localised or generalised, and may result from infection or from a non-infectious process.-Abdominal pain and tenderness:The main manifestations of...

  • Ileus
    Ileus
    Ileus is a disruption of the normal propulsive ability of the gastrointestinal tract.Ileus is commonly defined simply as bowel obstruction. However, authoritative sources define it as decreased motor activity of the GI tract due to non-mechanical causes...

  • Food allergies (often in conjunction with hives or swelling)
  • Cholecystitis
    Cholecystitis
    -Signs and symptoms:Cholecystitis usually presents as a pain in the right upper quadrant. This is known as biliary colic. This is initially intermittent, but later usually presents as a constant, severe pain. During the initial stages, the pain may be felt in an area totally separate from the site...

    , pancreatitis
    Pancreatitis
    Pancreatitis is inflammation of the pancreas. It occurs when pancreatic enzymes that digest food are activated in the pancreas instead of the small intestine. It may be acute – beginning suddenly and lasting a few days, or chronic – occurring over many years...

    , appendicitis
    Appendicitis
    Appendicitis is a condition characterized by inflammation of the appendix. It is classified as a medical emergency and many cases require removal of the inflamed appendix, either by laparotomy or laparoscopy. Untreated, mortality is high, mainly because of the risk of rupture leading to...

    , hepatitis
    Hepatitis
    Hepatitis is a medical condition defined by the inflammation of the liver and characterized by the presence of inflammatory cells in the tissue of the organ. The name is from the Greek hepar , the root being hepat- , meaning liver, and suffix -itis, meaning "inflammation"...

  • Food poisoning
  • In children, it can be caused by an allergic reaction to cow's milk proteins (Milk allergy or lactose intolerance
    Lactose intolerance
    Lactose intolerance, also called lactase deficiency or hypolactasia, is the inability to digest and metabolize lactose, a sugar found in milk...

    )

Sensory system and brain

Causes in the sensory system
Sensory system
A sensory system is a part of the nervous system responsible for processing sensory information. A sensory system consists of sensory receptors, neural pathways, and parts of the brain involved in sensory perception. Commonly recognized sensory systems are those for vision, hearing, somatic...

  • Movement: motion sickness
    Motion sickness
    Motion sickness or kinetosis, also known as travel sickness, is a condition in which a disagreement exists between visually perceived movement and the vestibular system's sense of movement...

     (which is caused by overstimulation of the labyrinthine canals of the ear)
  • Ménière's disease
    Ménière's disease
    Ménière's disease is a disorder of the inner ear that can affect hearing and balance to a varying degree. It is characterized by episodes of vertigo and tinnitus and progressive hearing loss, usually in one ear. It is named after the French physician Prosper Ménière, who, in an article published...



Causes in the brain
  • Concussion
  • Cerebral hemorrhage
  • Migraine
    Migraine
    Migraine is a chronic neurological disorder characterized by moderate to severe headaches, and nausea...

  • Brain tumor
    Brain tumor
    A brain tumor is an intracranial solid neoplasm, a tumor within the brain or the central spinal canal.Brain tumors include all tumors inside the cranium or in the central spinal canal...

    s, which can cause the chemoreceptors to malfunction
  • Benign intracranial hypertension and hydrocephalus
    Hydrocephalus
    Hydrocephalus , also known as "water in the brain," is a medical condition in which there is an abnormal accumulation of cerebrospinal fluid in the ventricles, or cavities, of the brain. This may cause increased intracranial pressure inside the skull and progressive enlargement of the head,...



Metabolic disturbances (these may irritate both the stomach and the parts of the brain that coordinate vomiting)
  • Hypercalcemia (high calcium
    Calcium in biology
    Calcium plays a pivotal role in the physiology and biochemistry of organisms and the cell. It plays an important role in signal transduction pathways, where it acts as a second messenger, in neurotransmitter release from neurons, contraction of all muscle cell types, and fertilization...

     levels)
  • Uremia
    Uremia
    Uremia or uraemia is a term used to loosely describe the illness accompanying kidney failure , in particular the nitrogenous waste products associated with the failure of this organ....

     (urea
    Urea
    Urea or carbamide is an organic compound with the chemical formula CO2. The molecule has two —NH2 groups joined by a carbonyl functional group....

     accumulation, usually due to renal failure
    Renal failure
    Renal failure or kidney failure describes a medical condition in which the kidneys fail to adequately filter toxins and waste products from the blood...

    )
  • Adrenal insufficiency
    Adrenal insufficiency
    Adrenal insufficiency is a condition in which the adrenal glands, located above the kidneys, do not produce adequate amounts of steroid hormones , primarily cortisol, but may also include impaired aldosterone production which regulates sodium, potassium and water retention...

  • Hypoglycemia
    Hypoglycemia
    Hypoglycemia or hypoglycæmia is the medical term for a state produced by a lower than normal level of blood glucose. The term literally means "under-sweet blood"...

  • Hyperglycemia
    Hyperglycemia
    Hyperglycemia or Hyperglycæmia, or high blood sugar, is a condition in which an excessive amount of glucose circulates in the blood plasma. This is generally a glucose level higher than 13.5mmol/l , but symptoms may not start to become noticeable until even higher values such as 15-20 mmol/l...



Pregnancy
  • Hyperemesis
    Hyperemesis gravidarum
    Hyperemesis gravidarum is a severe form of morning sickness, with "unrelenting, excessive pregnancy-related nausea and/or vomiting that prevents adequate intake of food and fluids." Hyperemesis is considered a rare complication of pregnancy but, because nausea and vomiting during pregnancy exist...

    , Morning sickness
    Morning sickness
    Morning sickness, also called nausea gravidarum, nausea, vomiting of pregnancy , or pregnancy sickness is a condition that affects more than half of all pregnant women. Related to increased oestrogen levels, a similar form of nausea is also seen in some women who use hormonal contraception or...



Drug reaction (vomiting may occur as an acute somatic
Somatic
The term somatic means 'of the body',, relating to the body. In medicine, somatic illness is bodily, not mental, illness. The term is often used in biology to refer to the cells of the body in contrast to the germ line cells which usually give rise to the gametes...

 response to)
  • alcohol
    Alcohol
    In chemistry, an alcohol is an organic compound in which the hydroxy functional group is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms....

     (being sick while being drunk
    Drunkenness
    Alcohol intoxication is a physiological state that occurs when a person has a high level of ethanol in his or her blood....

     or being sick the next morning, suffering from the after-effects, i.e., the hangover
    Hangover
    A hangover describes the sum of unpleasant physiological effects following heavy consumption of alcoholic beverages. The most commonly reported characteristics of a hangover include headache, nausea, sensitivity to light and noise, lethargy, dysphoria, diarrhea and thirst, typically after the...

    ).
  • opioid
    Opioid
    An opioid is a psychoactive chemical that works by binding to opioid receptors, which are found principally in the central and peripheral nervous system and the gastrointestinal tract...

    s
  • selective serotonin reuptake inhibitors
  • many chemotherapy
    Chemotherapy
    Chemotherapy is the treatment of cancer with an antineoplastic drug or with a combination of such drugs into a standardized treatment regimen....

     drugs
  • some entheogen
    Entheogen
    An entheogen , in the strict sense, is a psychoactive substance used in a religious, shamanic, or spiritual context. Historically, entheogens were mostly derived from plant sources and have been used in a variety of traditional religious contexts...

    s (such as peyote
    Peyote
    Lophophora williamsii , better known by its common name Peyote , is a small, spineless cactus with psychoactive alkaloids, particularly mescaline.It is native to southwestern Texas and Mexico...

     or ayahuasca
    Ayahuasca
    Ayahuasca is any of various psychoactive infusions or decoctions prepared from the Banisteriopsis spp. vine, usually mixed with the leaves of dimethyltryptamine-containing species of shrubs from the Psychotria genus...

    )


Illness (sometimes colloquially known as "stomach flu"—a broad name that refers to gastric inflammation caused by a range of viruses and bacteria.)
  • Norovirus (Formerly Norwalk virus or Norwalk agent)
  • Swine Flu
    Swine flu
    Swine influenza, also called pig influenza, swine flu, hog flu and pig flu, is an infection by any one of several types of swine influenza virus. Swine influenza virus or S-OIV is any strain of the influenza family of viruses that is endemic in pigs...


Emetics

An emetic, such as syrup of ipecac
Syrup of ipecac
Syrup of ipecac , commonly referred to as ipecac, is derived from the dried rhizome and roots of the ipecacuanha plant, and is a well known emetic .-Preparation:...

, is a substance that induces vomiting when administered orally or by injection. An emetic is used medically where a substance has been ingested and must be expelled from the body immediately (for this reason, many toxic and easily digestible products such as rat poison contain an emetic). Inducing vomiting can remove the substance before it is absorbed into the body. Ipecac abuse can cause detrimental health effects.

Salt
Salt
In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations and anions so that the product is electrically neutral...

 water and mustard
Mustard seed
Mustard seeds are the small round seeds of various mustard plants. The seeds are usually about 1 or 2 mm in diameter. Mustard seeds may be colored from yellowish white to black. They are important spices in many regional foods. The seeds can come from three different plants: black mustard , brown...

 water have been used since ancient times as emetics. Care must be taken with salt, as excessive intake can potentially be harmful.

Copper sulfate was also used in the past as an emetic. It is now considered too toxic for this use.

Social cues

It is quite common that, when one person vomits, others nearby become nauseated, particularly when smelling the vomit of others, often to the point of vomiting themselves. It is believed that this is an evolved
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...

 trait among primates. Many primates in the wild tend to browse for food in small groups. Should one member of the party react adversely to some ingested food, it may be advantageous (in a survival sense) for other members of the party also to vomit. This tendency in human populations has been observed at drinking parties, where excessive consumption of alcohol
Alcohol
In chemistry, an alcohol is an organic compound in which the hydroxy functional group is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms....

ic beverages may result in a number of party members vomiting nearly simultaneously, this being triggered by the initial vomiting of a single member of the party. This phenomenon has been touched on in popular culture: Notorious instances appear in the films Monty Python's The Meaning of Life (1983) and Stand By Me
Stand by Me (film)
Stand by Me is a 1986 American drama film directed by Rob Reiner. Based on the novella The Body by Stephen King, the film takes its title from the Ben E. King song of the same name, which plays over the end credits.-Plot:...

(1986).

Intense vomiting in ayahuasca
Ayahuasca
Ayahuasca is any of various psychoactive infusions or decoctions prepared from the Banisteriopsis spp. vine, usually mixed with the leaves of dimethyltryptamine-containing species of shrubs from the Psychotria genus...

 ceremonies
Ceremony
A ceremony is an event of ritual significance, performed on a special occasion. The word may be of Etruscan origin.-Ceremonial occasions:A ceremony may mark a rite of passage in a human life, marking the significance of, for example:* birth...

 is a common phenomenon. However, people who experience "la purga" after drinking ayahuasca, in general, regard the practice as both a physical and spiritual cleanse and often come to welcome it. It has been suggested that the consistent emetic effects of ayahuasca — in addition to its many other therapeutic properties — was of medicinal benefit to indigenous peoples of the Amazon
Amazon Basin
The Amazon Basin is the part of South America drained by the Amazon River and its tributaries that drains an area of about , or roughly 40 percent of South America. The basin is located in the countries of Bolivia, Brazil, Colombia, Ecuador, Guyana, Peru, and Venezuela...

, in helping to clear parasites from the gastrointestinal system.

There have also been documented cases of a single ill and vomiting individual inadvertently causing others to vomit, when they are especially fearful of also becoming ill, through a form of mass hysteria.

Context
Most people try to contain their vomit by vomiting into a sink, toilet, or trash can, as both the act and the vomit itself are widely considered embarrassing; vomit is also difficult to clean. On airplanes and boats, special bags are supplied for sick passengers to vomit into. A special disposable bag containing absorbent material that solidifies the vomit quickly is available, also, making it convenient and safe to keep (leakproof, puncture-resistant, odorless) until there is an opportunity to dispose of it conveniently.

People who vomit chronically (e.g., as part of an eating disorder
Eating disorder
Eating disorders refer to a group of conditions defined by abnormal eating habits that may involve either insufficient or excessive food intake to the detriment of an individual's physical and mental health. Bulimia nervosa, anorexia nervosa, and binge eating disorder are the most common specific...

 such as bulimia nervosa
Bulimia nervosa
Bulimia nervosa is an eating disorder characterized by binge eating and purging or consuming a large amount of food in a short amount of time, followed by an attempt to rid oneself of the food consumed, usually by purging and/or by laxative, diuretics or excessive exercise. Bulimia nervosa is...

) may devise various ways to hide this disorder.

Sound

An online study of people's responses to "horrible sounds" found vomiting "the most disgusting." Professor Cox of the University of Salford
University of Salford
The University of Salford is a campus university based in Salford, Greater Manchester, England with approximately 20,000 registered students. The main campus is about west of Manchester city centre, on the A6, opposite the former home of the physicist, James Prescott Joule and the Working Class...

's Acoustic Research Centre said that "We are pre-programmed to be repulsed by horrible things such as vomiting, as it is fundamental to staying alive to avoid nasty stuff." It is thought that disgust is triggered by the sound of vomiting to protect food from those possibly diseased nearby.

Miscellanea

  • Self-induced
    • Eating disorders (anorexia nervosa
      Anorexia nervosa
      Anorexia nervosa is an eating disorder characterized by refusal to maintain a healthy body weight and an obsessive fear of gaining weight. Although commonly called "anorexia", that term on its own denotes any symptomatic loss of appetite and is not strictly accurate...

       or bulimia nervosa
      Bulimia nervosa
      Bulimia nervosa is an eating disorder characterized by binge eating and purging or consuming a large amount of food in a short amount of time, followed by an attempt to rid oneself of the food consumed, usually by purging and/or by laxative, diuretics or excessive exercise. Bulimia nervosa is...

      )
    • To eliminate an ingested poison (some poisons should not be vomited as they may be more toxic when inhaled or aspirated; it is better to ask for help before inducing vomiting)
    • Some people who engage in binge drinking
      Binge drinking
      Binge drinking or heavy episodic drinking is the modern epithet for drinking alcoholic beverages with the primary intention of becoming intoxicated by heavy consumption of alcohol over a short period of time. It is a kind of purposeful drinking style that is popular in several countries worldwide,...

       induce vomiting to make room in their stomachs for more alcohol consumption.
    • People suffering from nausea may induce vomiting in hopes of feeling better.
  • After surgery
    Surgery
    Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...

     (postoperative nausea and vomiting
    Postoperative nausea and vomiting
    Postoperative nausea and vomiting is an unpleasant complication affecting about a third of the 10% of the population undergoing general anaesthesia each year. This equates to about two million people in the United Kingdom annually.-Impact:...

    )
  • Disagreeable sights, smells or thoughts (such as decayed matter, others' vomit, thinking of vomiting), etc.
  • Extreme pain, such as intense headache
    Headache
    A headache or cephalalgia is pain anywhere in the region of the head or neck. It can be a symptom of a number of different conditions of the head and neck. The brain tissue itself is not sensitive to pain because it lacks pain receptors. Rather, the pain is caused by disturbance of the...

     or myocardial infarction
    Myocardial infarction
    Myocardial infarction or acute myocardial infarction , commonly known as a heart attack, results from the interruption of blood supply to a part of the heart, causing heart cells to die...

     (heart attack)
  • Violent emotions
  • Cyclic vomiting syndrome
    Cyclic vomiting syndrome
    Cyclic vomiting syndrome or cyclical vomiting syndrome is a condition whose symptoms are recurring attacks of intense nausea, vomiting and sometimes abdominal pain and/or headaches or migraines...

     (a poorly-understood condition with attacks of vomiting)
  • High doses of ionizing radiation
    Ionizing radiation
    Ionizing radiation is radiation composed of particles that individually have sufficient energy to remove an electron from an atom or molecule. This ionization produces free radicals, which are atoms or molecules containing unpaired electrons...

     sometimes trigger a vomit reflex.
  • Violent fits of coughing, hiccups, or asthma
    Asthma
    Asthma is the common chronic inflammatory disease of the airways characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm. Symptoms include wheezing, coughing, chest tightness, and shortness of breath...

  • Nervousness
    Anxiety
    Anxiety is a psychological and physiological state characterized by somatic, emotional, cognitive, and behavioral components. The root meaning of the word anxiety is 'to vex or trouble'; in either presence or absence of psychological stress, anxiety can create feelings of fear, worry, uneasiness,...

  • Anxiety
    Anxiety
    Anxiety is a psychological and physiological state characterized by somatic, emotional, cognitive, and behavioral components. The root meaning of the word anxiety is 'to vex or trouble'; in either presence or absence of psychological stress, anxiety can create feelings of fear, worry, uneasiness,...

  • Overexertion (doing too much strenuous exercise can lead to vomiting shortly afterwards).
  • Rumination syndrome, an underdiagnosed and poorly understood disorder that causes sufferers to regurgitate food shortly after ingestion.

Other types

Fecal vomiting (aka stercoraceous vomiting) is a kind of vomiting, or emesis, in which half-digested matter is expelled from the intestines into the stomach
Stomach
The stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is...

, by spasmodic contractions of the gastric muscles, and then subsequently forcefully expelled from the stomach up into the esophagus
Esophagus
The esophagus is an organ in vertebrates which consists of a muscular tube through which food passes from the pharynx to the stomach. During swallowing, food passes from the mouth through the pharynx into the esophagus and travels via peristalsis to the stomach...

 and out through the mouth and sometimes nasal passages. Though it is not actual fecal matter that is expelled, it smells similar. Alternative medical terms for fecal vomiting are copremesis and stercoraceous vomiting. This form of aspiration usually leads to a severe aspiration pneumonia
Aspiration pneumonia
Aspiration pneumonia is bronchopneumonia that develops due to the entrance of foreign materials into the bronchial tree, usually oral or gastric contents...

, secondary to the massive number of bacteria present in the fecal matter. This form of pneumonia is often severe enough to be fatal.

Projectile vomiting refers to vomiting that ejects the gastric contents with great force. It is a classic symptom of infantile hypertrophic pyloric stenosis, in which it typically follows feeding and can be so forceful that some material exits through the nose.

Treatment

An antiemetic
Antiemetic
An antiemetic is a drug that is effective against vomiting and nausea. Antiemetics are typically used to treat motion sickness and the side effects of opioid analgesics, general anaesthetics, and chemotherapy directed against cancer....

 is a drug
Medication
A pharmaceutical drug, also referred to as medicine, medication or medicament, can be loosely defined as any chemical substance intended for use in the medical diagnosis, cure, treatment, or prevention of disease.- Classification :...

 that is effective against vomiting and nausea
Nausea
Nausea , is a sensation of unease and discomfort in the upper stomach with an involuntary urge to vomit. It often, but not always, precedes vomiting...

. Antiemetics are typically used to treat motion sickness
Motion sickness
Motion sickness or kinetosis, also known as travel sickness, is a condition in which a disagreement exists between visually perceived movement and the vestibular system's sense of movement...

 and the side-effects
Adverse effect (medicine)
In medicine, an adverse effect is a harmful and undesired effect resulting from a medication or other intervention such as surgery.An adverse effect may be termed a "side effect", when judged to be secondary to a main or therapeutic effect. If it results from an unsuitable or incorrect dosage or...

 of medications such as opioid
Opioid
An opioid is a psychoactive chemical that works by binding to opioid receptors, which are found principally in the central and peripheral nervous system and the gastrointestinal tract...

s and chemotherapy
Chemotherapy
Chemotherapy is the treatment of cancer with an antineoplastic drug or with a combination of such drugs into a standardized treatment regimen....

.

Antiemetics act by inhibiting the receptor sites associated with emesis. Hence, anticholinergics, antihistamines, dopamine antagonists, serotonin antagonists, and cannabinoids are used as anti-emetics.

Epidemiology

Nausea
Nausea
Nausea , is a sensation of unease and discomfort in the upper stomach with an involuntary urge to vomit. It often, but not always, precedes vomiting...

and or vomiting is the main complaint in 1.6% of visits to family physicians in Australia.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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