Colonoscopy

Source: MedlinePlus Health Topics, U.S. National Library of Medicine

Last synced 8/10/2026Status: primary verified

What are colonoscopy and flexible sigmoidoscopy? Colonoscopy and flexible sigmoidoscopy are procedures that let your doctor look inside your rectum and colon (large intestine). They use instruments called scopes. Scopes have a light and a tiny camera attached to a long, thin tube. These procedures let your doctor see problems such as inflamed tissue, ulcers, polyps , and cancer . Colonoscopy checks your entire colon and rectum. Flexible sigmoidoscopy checks the rectum and the lower colon (sigmoid colon) only. What is a virtual colonoscopy? A virtual colonoscopy also looks inside your rectum and part of your colon. But it does not use a scope. Instead, it is an x-ray test. Another name for this test is CT colonography. Who needs a colonoscopy, virtual colonoscopy, or flexible sigmoidoscopy? You may need a colonoscopy, virtual colonoscopy, or flexible sigmoidoscopy to find the cause of unexplained symptoms such as: Bleeding from your anus (the opening of the rectum through which stool passes out of your body) Changes in your bowel activity, such as diarrhea Pain in your abdomen (belly) Unexplained weight loss Doctors also use these procedures to screen for colon polyps and cancer. Screening is testing for diseases when you have no symptoms. It may find diseases at an early stage, when they are easier to treat. If aren't at higher risk for colorectal cancer, your health care provider will likely recommend you start getting screenings at age 45. If you are at higher risk, you may need to start getting screened for colorectal cancer earlier. There are also other tests to screen for colorectal cancer , including stool tests. Talk with your provider about which test is right for you and when and how often you should get it. How do you prepare for a colonoscopy, virtual colonoscopy, or flexible sigmoidoscopy? To prepare for a colonoscopy, virtual colonoscopy, or flexible sigmoidoscopy, you will need to: Talk with your doctor about any health problems you have and all of the

Educational only

This information is for general education and is not medical advice. Always talk to a licensed U.S. clinician about your situation, medications, or treatment decisions.