An upper endoscopy is a test in which your doctor uses a thin, flexible tube with a lens and light source to examine the lining of the upper part of your intestinal tract, which includes the esophagus, stomach and duodenum (first portion of the small intestine).  The test is used to evaluate symptoms of persistent abdominal pain, nausea, difficulty swallowing, and gastrointestinal bleeding.  During the procedure, biopsies (which are small tissue samples) can be taken to help test for Helicobacter pylori, a bacteria that can cause chronic stomach inflammation and ulcers.  If a narrowing is found in the esophagus, it can be dilated (stretched) to alleviate difficulty with swallowing.  Preparation for the procedure includes not eating or drinking for six hours prior to the procedure.  Patients are sedated for the procedure and typically experience little or no discomfort.