Colonoscopy is done for patients who have problems like indigestion, loose stools, irregular bowel movements, blood in the excreta, etc., for large span of time.

To rule out colon cancer, Colonoscopy is used. The scope, consisting of a very thin wire like material, with a light at tip is inserted through the rectum, and the medical professional examines the whole colon, looking for abnormalities. If any abnormality is found as tissue growth, or looks different, with the same instrument, a piece of it is taken out for biopsy. A diagnosis is made and appropriate measures are suggested to the patient.