Peptic ulcers are the result of a wide variety of factors, with H. pylori probably being one of the more significant. H. pylori has been most strongly associated with gastritis and duodenal ulcer disease. The relationship of H. pylori to gastric ulcers is less substantial. The eradication of H. pylori can be achieved in the majority of patients with triple antibiotic therapy. However, resistance to metronidazole occurs readily. Eradication of H. pylori can change the course of duodenal ulcer disease by decreasing recurrence rate from 80% to zero. Nonetheless, treatment for H. pylori should only be done in randomized trials at the current time because of the lack of completely effective therapy and the high risks of side effects. The mechanism by which H. pylori influences duodenal ulcer recurrence is unclear. Pathogenic mechanisms of the organism also need to be further elucidated.