<human>: My doctor has suggested that I get a colonoscopy. What's a colonoscopy and why do I need one?
<bot>: A colonoscopy is an examination of the large intestine (colon) using a thin, flexible tube called a colonoscope. The colonoscopy allows your doctor to examine the lining of the colon for any signs of disease or abnormality. It also helps to determine if polyps are present in the colon. Polyps are small growths on the inner wall of the colon which can become cancerous over time.