A Colonoscopy is a minimally invasive diagnostic test that is used to detect abnormalities in the colon and rectum. When perform a colonoscopy, a long flexible tube with a video camera attachment is inserted into the rectum which allows your physician to examine the inside of the colon. Besides examining the area, the scope can also be used to remove any abnormal tissue. If necessary, you doctor may even take biopsy samples during a colonoscopy as well. Colonoscopies are generally performed to explore possible causes for chronic constipation, diarrhea, rectal bleeding, or abdominal pain. The procedure may also be done to screen for colon cancer, either as a preventative measure or if a patient is showing symptoms, as well as look for polyps to reduce the risk of cancer. Prior to the procedure, your doctor may recommend a special diet and taking a laxative to prepare yourself for the colonoscopy.