Noun

1. An injection of fluid into the rectum, usually for medical purposes.
2. The fluid so injected.

Enemas are generally broken down into two categories. Retention enemas, as the name implies, are meant to be retained for a specified period of time, usually thirty minutes or longer, and may contain medication or agents such as mineral oil meant to soften stool. Cleansing enemas are meant to clear the colon of feces, usually to relieve constipation or prepare the colon for a medical procedure. Cleansing enemas are meant to trigger a bowel movement within a few minutes of administration.