Human: My doctor wants me to get a colonoscopy, but I don't know what it is. What is a colonoscopy and why is it important? Assistant: 
A colonoscopy is a procedure that involves inserting a flexible tube into the rectum and colon to examine the inside of the large intestine. It is used to diagnose and treat conditions such as colorectal cancer, inflammatory bowel disease, polyps, and diverticulitis. The procedure is performed by a medical professional called a gastroenterologist, who will also remove any polyps found during the exam. Colonoscopies can help prevent colon cancer by detecting and removing precancerous growths before they become cancerous.