About Enemas

An enema is the introduction of liquid into the large intestine through the anus. Enemas may be prescribed for certain health conditions, as preparation for medical tests, and are sometimes used as a home treatment for constipation. Some alternative therapies involve the use of very large enemas, which are referred to as "colonics."

Type

• Most enemas used are cleansing enemas, used to empty normal stool from the bowel. These may consist of plain tap water, a saline solution or soapy water. Cleansing enemas are generally held for five to 10 minutes, after which the patient has a bowel movement. Retention enemas contain a smaller amount of lubricating fluid, such as oil, and are held for 30 to 60 minutes. These are typically used to soften hardened stool, such as in severe cases of constipation. Occasionally, medicated enemas are administered to treat conditions affecting the large intestine.

Effects

• Enemas generally create a sensation of fullness in the intestines, followed rapidly by a powerful urge to have a bowel movement. Typically, a bowel movement is inevitable five to 10 minutes after the enema is administered. Constipation is usually relieved by a cleansing enema, but in some cases only the enema solution is expelled and other measures are necessary.

Function

• Enemas stimulate peristalsis, a pattern of muscular contractions within the intestines. Peristalsis moves food throughout the digestive system and triggers the urge to defecate. Some types of enemas soften the feces by drawing water from the intestines, and others provide lubrication to ease bowel movements. In some cases, medication is administered directly to a diseased or infected large intestine using an enema.

Risk Factors

• Excessive use of enemas may cause side effects such as fluid overload and reduced muscle tone in the anal sphincter. People with heart disease should consult their doctor before using an enema; arrhythmias occasionally result from the insertion of the enema tube. Enemas should never be used on someone who has abdominal pain, because the increased fluid volume in the intestine can cause a burst appendix if the person happens to have appendicitis.

History of

• Enemas administered during the 17th, 18th, and early 19th centuries were referred to as "clysters." They were administered using a clyster syringe--a large metal syringe with a nozzle and plunger. The most common reasons for administering enemas during this time were constipation, nausea and in preparation for childbirth. Most enemas were administered by apothecaries and midwives, although specialized clyster syringes were available for self-administration. Modern enema bags and bulb syringes replaced clyster syringes during the 19th century.