The bacterium Helicobacter pylori, or H. pylori, has recently been shown to be strongly associated with ulcers and gastritis, although the precise cause of gastrointestinal ulcers is still unknown. Although hydrochloric acid in the stomach is required for the development of a peptic ulcer, levels of stomach acid are not necessarily elevated. About 30 to 40 percent of patients with duodenal ulcers have increased acid secretion while most patients with gastric ulcer have either normal or below normal acid secretion rates. Heredity probably also plays a role. Stress and the use of nonsteroidal anti-inflammatory drugs such as aspirin may cause ulceration by interfering with cytoprotection.
Stress is by no means a universal factor in causing peptic ulcer disorders.
Cigarette smoking may cause duodenal ulcers and has been shown to delay ulcer healing. Alcohol can cause irritation of the lining of the stomach but has not been proven to cause duodenal ulceration. Also, contrary to popular belief, spicy foods do not appear to cause peptic ulcers. Abdominal pain is a common symptom, usually described as a gnawing ache or burning sensation relieved by milk or antacids. The location and type of pain also depend upon the type of ulcer.