Colonoscopy is a special test that allows your gastroenterologist to look directly into the last part of the intestines(called "colon" or "large intestine") to help find out why the child is having bleeding, diarrhea, and stomach pain. After the doctor gives you medicines that will help you sleep, he/she will take a  tiny bendable tube fitted with a camera and light to look inside your bottom (rectum). Tiny tissue samples (biopsies) are usually taken during the test, the size of a pinhead. This can help your doctor explain why you might have tummy (stomach) pain, watery poops (diarrhea) or bleeding when you go to the bathroom.