An injection of a liquid into the rectum or colon with the purpose of stimulating a bowel movement.
Generally given as a prepacked sodium phosphate enema, or as a large volume tap water enema (which may contain different ingredients such as salt, soap, etc). Usually given to treat constipation or to clear the bowel before a medical procedure. Prepacked enemas typically require a waiting period of two to five minutes for the enema to be effective. Large volume tap water enemas are usually effective in five to twenty minutes. The waiting period is recommended in order to soften the stool, and to allow time for contractions of the colon (peristalsis) to begin. Although a waiting period is recommended, the cleansing enema is not the same as a retention enema, which usually contains oil to soften the stool, or medication that is absorbed through the colon.
Small volume mini-enemas typically contain a very small amount of either liquid bisacodyl or docusate sodium. The solutions stimulate the colon and result in bowel movement, usually within fifteen to thirty minutes. These enemas are also classified as cleansing enemas.