No scientific evidence supports the alleged benefits of colon cleansing* and it "has no known medical value and risks damage to the rectum or bowel." The bowel itself is "not dirty” and, unless disease or medication interfere, "nature does a fine job of clearing out wastes."* Certain enema preparations have been associated with Myocardial infarction|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 defecation|defecate and some herbs may reduce the effectiveness of prescription drugs.*
HistoryThe rationale for colon cleansing is the concept of "auto-intoxication", the idea that food enters the intestine and rots.* The ancient Egyptians believed that toxins formed as a result of decomposition within the intestines, and moved from there into the circulatory system causing fever and the development of pus. The Ancient Greeks adopted and expanded the idea, applying their belief in the Humorism|four humours. In the 19th century, studies in biochemistry and microbiology seemed to support the autointoxication hypothesis, and mainstream physicians promoted the idea.* The idea was promoted most strongly by Ilya Ilyich Mechnikov (1845-1916), who thought that these toxins could shorten the lifespan. Over time, the concept broadened to "auto-intoxication", which supposes that the body cannot fully dispose of its waste products and toxins, which then accumulate in the intestine.* In some cases, the concept led to radical surgeries to remove the colon for unrelated symptoms.*Auto-intoxication enjoyed some favor in the medical community from the late nineteenth to the early twentieth century, but was discarded as advances in science failed to support its claims.* A 1919 paper Origin of the so-called auto-intoxication symptom in the Journal of the American Medical Association* marked the beginning of the rejection of the auto-intoxication hypothesis by the medical community.*
Despite this, "auto-intoxication" persists in the public imagination. The practice of colon cleansing has undergone a resurgence in the Alternative medicine|alternative medical community, supported by testimonials and anecdotal evidence|anecdotal evidence and promoted by manufacturers of colon-cleansing products.*
Medical imagingColon cleansing is done for its own sake, prior to surgery, Colonoscopy#Preparation|colonoscopy, or similar procedures. The colon is cleansed of solid matter with a regimen of liquid foods then a day before the procedure a whole bowel irrigation can be performed.
Relationship to medical symptomsThe symptoms that are attributed to auto-intoxication—headache, fatigue (medical)|fatigue, Anorexia (symptom)|loss of appetite and Annoyance|irritability—are actually caused by mechanical distention within the bowel, such as irritable bowel syndrome, rather than toxins from putrefying food.* The benefits anecdotally attributed to colon cleansing are vague and the claims made by manufacturers and practitioners are based on a flawed understanding of the body.* There is little evidence of actual benefit to the procedure, and no evidence that it can alleviate the symptoms that are attributed to the theories of colon cleansing.*
Complications and risksThe human body naturally removes waste material, and colon cleansing is not necessary except preparatory to a colonoscopy.* Colon cleansing may disrupt the balance between bacteria and natural chemicals in the bowel, and may interfere with the colon's ability to shed dead cells.*Other rare but serious complications include gastrointestinal perforation from improper insertion,* and amoebiasis|amoebic infection from poorly sterilised equipment.* Some colon-cleansing regimens disrupt fluid and electrolyte balance, which may lead to dehydration and salt depletion, whilst repeated or excessive cleansing programs can lead to anemia and malnutrition.* Excessive use of enemas has also been associated with cardiac problems, such as heart failure,* and myocardial infarction|heart attacks related to water-electrolyte imbalance|electrolyte imbalances when performed as coffee enema.* The frequent use of enemas or other colon-cleansing tools may lead to dependence and an inability to defecate without assistance or withdrawal symptoms.*
Herbs that are consumed for colon cleansing and taken as oral preparations may also interfere with Absorption (pharmacokinetics)|drug absorption and effectiveness of prescription drugs.*