What is a colonoscopy?

A colonoscopy is an outpatient procedure in which the inside of the large intestine (colon and rectum) is examined. A colonoscopy is 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 screening colonoscopy is recommended for anyone without risk factors for colorectal cancer starting at 50 years of age. The timing of your colonoscopies varies depending on the findings of your test. You may need to have a colonoscopy at a younger age if you have an increased risk of colon cancer. These risk factors can include:

  • Having familial polyposis syndrome (a condition that runs in your family and is linked to an increased risk of forming polyps).
  • Having inflammatory bowel disease.
  • Having first degree relatives with colon cancer.

Last reviewed by a Cleveland Clinic medical professional on 10/27/2019.


  • American College of Gastroenterology. Colonoscopy. Accessed 10/28/2018.
  • The National Institute of Diabetes and Digestive and Kidney Diseases. Colonoscopy. Accessed 10/28/2018.

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