A colonoscopy is an endoscopic procedure where a long, thin, flexible tube or “scope” is placed into the rectum and advanced through the entire colon (large intestine). The scope has a light and a camera on the end of it which allows the physician to examine the lining of the colon. A colonoscopy may be performed to diagnose the cause of GI symptoms such as diarrhea, constipation, bleeding, abdominal pain, or abnormal x-ray results. A colonoscopy may also be performed on an asymptomatic patient at age 50, or sooner depending on the patient’s history, to screen for colorectal cancer and polyps. A colonoscopy can also be helpful in diagnosing inflammatory bowel disease (IBD) or irritable bowel syndrome (IBS).