Esophageal ulcer: A crater in the lining of the esophagus that is created by the corrosive acidic digestive juices secreted by the stomach cells. Ulcer formation is related to the presence of Helicobacter pylori (H. pylori) bacteria in the stomach, use of anti-inflammatory medications, and cigarette smoking. Ulcer pain may not correlate with the presence or severity of ulceration. Diagnosis is made through barium X-ray or endoscopy. Complications of ulcers include bleeding and perforation. Treatment includes using antibiotics to eradicate H. pylori, eliminating risk factors, and preventing complications.