Colon Irrigation or Colon cleansing (also known as colon therapy) encompasses a number of alternative medical therapies claimed to remove nonspecific toxins from the colon and intestinal tract by removing any accumulations of feces. Colon cleansing may be branded colon hydrotherapy, a colonic or colonic irrigation. During the 2000s internet marketing and infomercials of oral supplements supposedly for colon cleansing increased.

Some forms of colon hydrotherapy use tubes to inject water, sometimes mixed with herbs or with other liquids, into the colon via the rectum using special equipment. Oral cleaning regimens use dietary fiber, herbs, dietary supplements, or laxatives. People who practice colon cleansing believe that accumulations of putrefied feces line the walls of the large intestine and that these accumulations harbor parasites or pathogenic gut flora, causing nonspecific symptoms and general ill-health. This "auto-intoxication" hypothesis is based on medical beliefs of the Ancient Egyptians and Greeks and was discredited in the early 20th century.

There is no scientific evidence for the alleged benefits of colon cleansing. Certain enema preparations have been associated with heart attacks and electrolyte imbalances, and improperly prepared or used equipment can cause infection or damage to the bowel. Frequent colon cleansing can lead to dependence on enemas to defecate and some herbs may reduce the effectiveness of or increase the risks associated with the use of prescription drugs.