Doctors use endoscopes to evaluate the stomach and small bowel. Endoscopy refers to the examination of the bowel using a scope, a long, thin tube with a light and a camera at one end while the images obtained are displayed on a monitor. The scopes also have channels which allow instruments to be passed down them, to treat lesions, to obtain biopsies, or to mark the location of a lesion with a tattoo to aid a surgeon in locating it.

After you receive a sedative, the doctor passes the scope through your mouth. A regular endoscope is capable of examining the esophagus, stomach and the first portion of the small bowel, known as the duodenum.