An enema is a technique in which a solution is administered into a person's rectum to stimulate the release of large bowel movements and clean the large intestine. It is used to relieve persistent constipation or to clear the colon before various procedures, such as x-rays or other examinations. In some cases, an enema will be self-administered. In other cases, a physician or other medical professional will perform the procedure.

Enemas work by softening the feces and distending the colon and rectum. A combination of water and a mild soap or saline is often used in the solution. Enemas are also available in prepackaged solutions with various active ingredients. 

Before using an enema, patients should consult their physician. Conditions of concern regarding enemas include kidney disease, pregnancy and breastfeeding, and sodium-restricted diets. If the enema is to be self-administered, patients should check water temperature with a thermometer to ensure that it is not too hot.

Enemas can be taken using several positions. Most involve lying down or bending over and bending the knees. The tip of the enema bottle is inserted into the rectum and the solution is squeezed or allowed to flow inside.

Patients who experience a strong cramp after administering an enema should not stand up. This will add gravity to the force generated by the colon that is trying to expel the enema and fecal matter. Standing up at this point greatly increases the chances for an accident. Instead, patients should wait for 10 to 15 seconds while the pressure passes and then get up and sit on the toilet to evacuate their bowels.