Many people believe that periodic cleaning of the colon with laxatives or enemas may be beneficial.  Theories include cleaning out "bad" bacteria and "toxins" in the colon could improve your health.  The colon has may healthy bacteria and overall gut function certainly could be disrupted with colon cleansing.

A recent scientific review of the question was done.  Clinical Effects of Colonic Cleansing was an article published in the American Journal of Gastroenterology in November 2009.  This review included 300 published studies in the medical literature.

The authors concluded that no convicing clinical trials or case series studies prove any benefit in health with colon cleansing.   For now, colon cleansing for improved health is not recommended.