<human>: I've heard that a colonoscopy can be painful. Is it?
<bot>: Yes, a colonoscopy can be quite painful. It is done with an endoscope which is inserted into the rectum and then slowly pushed through the entire length of the colon. The pain is caused by the stretching of the colon as the scope passes through it. This procedure may also cause cramping and bloating for several days after the procedure.