Several recent studies have suggested the eradication of Helicobacter pylori (H. pylori) can increase the platelet count in patients with chronic idiopathic thrombocytopenic purpura (ITP). A systematic review of the literature published in English shows that overall platelet responses were observed in over 50% of the patients after successful eradication. The response rate tended to be higher in countries with a high prevalence ratio of H. pylori infection in background population, in patients with less severe degree of thrombocytopenia and in those with shorter disease duration. The detection and eradication of H. pylori should be considered as the first line of treatment in all Japanese patients with chronic ITP.