Helicobacter pylori is a unique pathogen and the leading cause of chronic gastric inflammation. For many individuals the organism is of low virulence, causing only mild inflammation and generating few, if any, dyspeptic symptoms. For those with more severe inflammation, H. pylori infection may be causal in the generation of dyspeptic symptoms. H. pylori infection appears to be the dominant factor in peptic ulcer disease. Events considered to be of importance are a disturbed gastrin homeostasis and the development of gastric metaplasia in the bulb. The most important argument in support of the dominant role of H. pylori in duodenal ulcer disease is the markedly reduced ulcer relapse after successful eradication. Eradication proves to be difficult, presumably because of the peculiar habitat of the organism. Currently the best pharmacologic approach is triple therapy, combining a bismuth salt, metronidazole, and amoxycillin or tetracycline.