The Serpent and the Rainbow is a book (1985) by ethnobotanist and researcher Wade Davis

Wade Davis

Edmund Wade Davis is a Canadian anthropologist, ethnobotanist, author and photographer whose work has focused on worldwide indigenous cultures, especially in North and South America and particularly involving the traditional uses and beliefs associated with psychoactive plants...

. He investigated Haitian Vodou and the process of making zombies. He studied ethnobotanical

Ethnobotany

Ethnobotany is the scientific study of the relationships that exist between people and plants....

 poisons, discovering their use in a reported case of a contemporary zombie, Clairvius Narcisse

Clairvius Narcisse

Clairvius Narcisse was a Haitian man said to have been turned into a living zombie by a combination of drugs. His case was the subject of a book, The Serpent and the Rainbow.-History:...

.

The book inspired a dramatic horror film, The Serpent and the Rainbow (1988). Davis was very vocal about his displeasure with the final result.

Criticism

Davis' claims were criticized for a number of scientific inaccuracies. Scientists doubted his assertion that Haitian witchdoctors could keep zombies in a state of pharmacologically induced trance for many years. In 1988, a response from Davis was published in the journal Science in which he reviewed the reasons for the Voodoo Science article's harsh criticism and suggested a number of reasons that its conclusions may not have applied to his findings including the variability of formulations, possible errors in the testing performed on the samples he brought back, the possibility that the tetrodotoxin-based mixture may have had ingredients that improved blood-brain barrier transmission of the tetrodotoxin, and the nature of folk medicine with respect to success rates (i.e. that very few successes are required in order to establish credibility).

Davis presented the case of Clairvius Narcisse

Clairvius Narcisse

Clairvius Narcisse was a Haitian man said to have been turned into a living zombie by a combination of drugs. His case was the subject of a book, The Serpent and the Rainbow.-History:...

, a man who had been a zombie for 2 years, as showing that the zombification process was more likely the result of a complex interaction of tetrodotoxin

Tetrodotoxin

Tetrodotoxin, also known as "tetrodox" and frequently abbreviated as TTX, sometimes colloquially referred to as "zombie powder" by those who practice Vodou, is a potent neurotoxin with no known antidote. There have been successful tests of a possible antidote in mice, but further tests must be...

, a powerful hallucinogen called Datura

Datura

Datura is a genus of nine species of vespertine flowering plants belonging to the family Solanaceae. Its precise and natural distribution is uncertain, owing to its extensive cultivation and naturalization throughout the temperate and tropical regions of the globe...

, and cultural forces and beliefs.

In the book, Davis does not suggest that the zombie powder containing tetrodotoxin was used for maintaining "mental slaves" but for producing the initial death and resurrection that convinced the victim and those who knew them that they had become zombies. The zombies, such as Clairvius Narcisse

Clairvius Narcisse

Clairvius Narcisse was a Haitian man said to have been turned into a living zombie by a combination of drugs. His case was the subject of a book, The Serpent and the Rainbow.-History:...

, were kept biddable by regular doses of the poisonous zombi cucumber, Datura stramonium

Datura stramonium

Datura stramonium, known by the common names Jimson weed, devil's trumpet, devil's weed, thorn apple, tolguacha, Jamestown weed, stinkweed, locoweed, datura, pricklyburr, devil's cucumber, Hell's Bells, moonflower and, in South Africa, malpitte and mad seeds, is a common weed in the...

which produces amnesia, delirium and suggestibility.