The available literature on the relationship between several diseases and Helicobacter pylori (H. pylori) is reviewed. Duodenal ulcer, gastric ulcer, complicated peptic ulcer, abdominal symptoms and gastroduodenal mucosal damage during the use of non-steroid anti-inflammatory drugs (NSAIDs), non-ulcer dyspepsia (NUD) and gastric malignancy are discussed. The case for and against eradication is critically discussed. Eradication of H. pylori should be pursued in all patients with peptic ulcer disease, whether they are using NSAIDs or not. Eradication of H. pylori in the treatment of NUD should be considered experimental. Treatment aimed at the eradication of H. pylori should be considered in all patients with low-grade malignant mucosa-associated lymphoid tissue (MALT) lymphoma and in all patients with Ménétrier's disease. Finally, this treatment should be considered in a subset of H. pylori-infected patients who possibly are at an increased risk of gastric cancer: patients with a strong family history of gastric carcinoma and patients in need of long-term treatment with a proton-pump inhibitor. In view of the importance of patient compliance, the risk of side-effects and the possibility of inducing metronidazole resistance when treatment with a metronidazole-containing regimen is used, treatment aimed at the eradication of H. pylori should be carefully implemented and monitored.