No scientific evidence supports the alleged benefits of colon cleansing.[2] The bowel itself is not dirty and barring drugs or disease, cleans itself naturally without need for assistance.[3] Some types of colon cleansing present potential hazards; the equipment used during colon cleansing has caused damage to the rectum in a small number of individuals, and caused amoebiasis when improperly sterilized. Certain enema preparations have been associated with heart attacks and electrolyte imbalances. Frequent colon cleansing may interfere with the proper functioning of the colon and can lead to dependence on laxatives or enemas to defecate. Some herbs used may also interact with or reduce the effectiveness of prescription drugs.[4]

Johns Hopkins doctors advise against colonics because of concerns about the potential for side effects.

Do most diseases begin in the colon? Is your bowel a cesspool? Does it harbor toxins that are harmful to your health? Some alternative health practitioners would have you believe that the answer to these questions is “yes.”

Treatments such as colonics are touted to detoxify the body and to ease the symptoms of conditions as wide ranging as asthma, arthritis, sinus problems, chronic fatigue, and constipation. But the medical truth is that colonics have never been rigorously tested in clinical trials.

Colonics -- What’s involved. During a colonic, a colon hydrotherapist inserts a rubber tube through the rectum and into the colon, sometimes as far as 30 inches. Up to 20 gallons of warm or cool water—possibly supplemented with soap, herbs, coffee, enzymes, minerals, or other substances—is then pumped into the rectum and allowed to sit for a few seconds to a few minutes while the stomach is massaged to loosen feces that are believed to have hardened in the colon (and are claimed to be the source of the toxins). The water is then drained out of the body through a second tube, bringing the fecal matter with it. This process is typically repeated several times to completely cleanse the bowel.

Colonics -- The risks. While removing hardened feces from your colon may sound like a reasonable way to improve your health, the risks of colonics should give you pause— particularly if you are over age 65 or have a bowel disease such as diverticulitis, Crohn’s disease, or ulcerative colitis, all of which increase your chances of experiencing a complication from the procedure.

In general, the dangers of undergoing colonics can be placed into four categories:

1. during a colonic the bowel wall can be perforated by the tip of the rubber tubing or by the use of too much water pressure and can lead to a potentially life-threatening infection;

2. you can have an allergic reaction to the nozzle at the tip of the rubber tubing (in particular, if you are allergic to latex) or to one of the cleansing substances added to the water;

3. you can develop an imbalance in electrolytes such as potassium and sodium, since colonics rinse away minerals that are normally absorbed into the bloodstream from the large intestine;

4. you can be infected with bacteria and viruses if the equipment is not properly sterilized between treatments. (Most colon hydrotherapists use disposable, sterile tubing, so this is less of a risk than in the past.)

The bottom line on colonics. Today, experts in the medical community—including doctors at Johns Hopkins—look on colonics as a questionable procedure, and advise against its practice because of concerns about the potential for side effects of colonics. While we are not opposed to alternative and complementary health practices that have been proven to be safe and effective, we do not advise colonics because it goes against a basic medical principle: First, do no harm.