Helicobacter pylori and gastrointestinal disease.

New paradigms are few and far between. The discovery that peptic ulcer disease is the result of an infection by a previously unrecognized microorganism rather than the consequence of excess secretion of gastric acid aptly qualifies as a paradigm shift. Eradication of Helicobacter pylori from the stomach by antibacterial agents heals ulcers at least as effectively as H2-blockers. Further, eradication of the organism results in long-term cures of peptic ulcers. In contrast, the relapse rate in patients successfully treated with H2-blockers exceeds 50% in the first year after healing. Also of interest is the role of H. pylori in gastric cancer.