A gastroscopy is an examination that allows us to look directly at the upper part of the gastrointestinal tract: the esophagus (the tube that food passes down to reach the stomach); the stomach and around the first bend of the small intestine (duodenum). In order to do this, a thin flexible tube called a gastroscope or endoscope, which has a light at one end, is used. It is passed through the mouth, down the esophagus, and into the stomach by a specially trained doctor or nurse called an endoscopist. The tube is thinner than your little finger. It will not get in the way of your breathing at any time, as it passes down your esophagus and not your windpipe. Sometimes biopsies (small tissue samples) are taken and sent for analysis. The biopsies that were taken are about the size of a match head and will not cause you any pain.