Helicobacter pylori infection is now recognised as a worldwide problem. It is the most common cause of chronic gastritis, and is strongly linked to peptic ulcer disease and gastric cancer. While the infection is usually acquired in childhood, there is typically a long period of latency with disease manifestations not appearing until adulthood. Gastric cancer does not usually manifest until old age. The infection has a high morbidity rate, but a low mortality rate and is curable with antibiotic therapy.