Gastric cancer is the second most common fatal malignant neoplasm in the world. In mainland China, gastric cancer is now the second most common malignant neoplasm, while in Hong Kong the mortality rate ranked fourth of all cancers in 1995. Dietary factors seem to be involved in gastric carcinogenesis, and beta carotene, selenium, and vitamin E (tocopherols) have been shown to help reduce gastric cancer mortality. Prospective case-control studies have shown an increased risk for the development of gastric cancer of between 2.8 and 6.0 among carriers of Helicobacter pylori. In addition, cagA-positive strains of Helicobacter pylori have been found to be associated with gastric cancer and duodenal ulceration. The exact role of Helicobacter pylori in gastric carcinogenesis is still being investigated. Helicobacter pylori eradication programmes to help prevent gastric cancer are being conducted in China and other parts of the world. In high-risk areas such as China, a combination approach that includes Helicobacter pylori eradication and dietary supplementation may be necessary.