A colonoscopy is a procedure that allows a gastroenterologist to carefully examine the lining of the colon and rectum using a thin, flexible instrument equipped with a camera.

Colonoscopy is commonly used for colorectal cancer screening and to investigate gastrointestinal symptoms. During the procedure, your physician can identify abnormalities, take tissue samples when appropriate and remove certain polyps.

Your gastroenterologist may recommend a colonoscopy for several reasons, including:

• Routine colorectal cancer screening

• A personal history of colon polyps

• A family history of colorectal cancer or polyps

• Rectal bleeding or blood in the stool

• Changes in bowel habits

• Persistent diarrhea or constipation

• Unexplained abdominal symptoms

• An abnormal or positive stool-based screening test

• Follow-up of a previous colonoscopy

Your physician will consider your age, symptoms, medical history and individual risk factors when determining whether a colonoscopy is appropriate.

Colonoscopy plays an important role in colorectal cancer prevention and early detection because it allows your gastroenterologist to identify and remove certain precancerous polyps during the procedure.

For adults at average risk, colorectal cancer screening generally begins at age 45. Some people may need to begin screening earlier or undergo colonoscopy more frequently because of family history, previous polyps or other risk factors.

Not sure when you're due?
Read our guide: When Is My Next Colonoscopy?