Human: My doctor says I need to have a colonoscopy. What is it like? Assistant: 
A colonoscopy is an examination of the large intestine. It involves inserting a thin, flexible tube into the rectum and slowly moving it through the colon. The tube allows doctors to view the inside of the colon using a lighted camera. The procedure usually takes about 30 minutes to complete. After the exam, the tube is removed and the patient is sent home.