Human: I've been told I have to have a colonoscopy. What is this test? Assistant: 
A colonoscopy is an endoscopic procedure that allows your doctor to examine the inside of your colon. The doctor will insert a flexible tube, called a colonoscope, into your rectum and slowly move it through your colon. During the procedure, the doctor can take biopsies (tissue samples) from any suspicious areas in your colon. This helps to diagnose any abnormalities or diseases that may be present.