Helicobacter pylori and peptic ulcer disease.

Since William Beaumont's classic description of gastric physiology in 1847, the focus of clinical practice and basic research concerning gastric and duodenal ulcers has centered on the secretion of acid and pepsin. In addition to these well-known factors (largely determined by heredity, age, and oral intake), the search for other agents that alter the mucosal barrier has identified a bacillus, Helicobacter pylori, as a significant agent in the development of chronic gastritis and benign gastric and duodenal ulcers. This review explores the scientific evidence for an important causal role of H. pylori in the development of peptic ulcers on the basis of pathologic, pathophysiologic, and pharmacologic data.