MODEL RELEASED. Colonic irrigation. Practitioner massaging a patient's lower abdomen during colonic irrigation. This is a procedure in which the colon (part of the large intestine) is flushed out with water or another liquid. The liquid is introduced through a tube (seen running from the tanks at upper left) placed into the anus. It is said to improve the health of the patient by removing harmful bacteria and waste. The procedure is controversial, however, as gut bacteria are generally beneficial, and the risks associated with the process outweigh any benefits.