A colonoscopy is an exam that views the inside of the colon (large intestine) and rectum, using a tool called a colonoscope. The colonoscope has a tiny camera attached to a flexible tube that can reach the length of the colon.

Colonoscopies are commonly used to evaluate gastrointestinal symptoms, such as rectal and intestinal bleeding, abdominal pain, or changes in bowel habits. Colonoscopies are also performed in individuals without symptoms to check for colorectal polyps or cancer.

A preventive-screening colonoscopy is recommended for anyone 50 years of age and older, and for anyone with a family history of colon problems.

Learn more from the Mayo Clinic online.