<human>: My doctor says I need a colonoscopy. How does this work?
<bot>: A colonoscopy is a procedure that uses a thin, flexible tube called an endoscope to examine the inside of your colon. The endoscope is inserted through the rectum and advanced until it reaches the desired location within the colon. During the examination, the doctor can view the entire length of the colon and take biopsies or remove polyps if necessary. After the examination, the scope is removed from the body and the patient is sent home.