Treatment guidelines for patients with idiopathic thrombocytopenic purpura (ITP) have been changed recently due to the clinical application of Helicobacter pylori (H. pylori) eradication but there has been no detailed multi-center analysis of the hematological effects of H. pylori eradication. The Clinical Hematology Forum consists of 11 large hematological departments and divisions in the Hokkaido area. We sent questionnaires to these 11 hematological departments and divisions in March 2003 to obtain information on current treatment strategies for patients with ITP and hematological results after the eradication of H. pylori. Questionnaires were returned by 9 (81.8%) of the 11 departments. Doctors in all hospitals had experience in diagnosis and treatment of H. pylori infection. Diagnostic examinations for H. pylori infection were performed in 54.3% of the registered cases. H. pylori infection was detected in 68.1% of the examined cases, and eradication treatment was performed in 87.7% of H. pylori-positive patients. H. pylori was eradicated in 52 (83.9%) of the 62 patients in whom the results of treatment could be evaluated. Among the patients whose platelet counts were less than 10.0 x 10(4)/microl, platelet recovery was observed in 48.8% of cases with successful eradication, a percentage similar to previously reported percentages in Japan. There was no prognostic factor to predict good responders before eradication treatment. Since the side effects of eradication treatment, including gastrointestinal symptoms and skin eruptions, were not serious, this method might become a front-line treatment for patients with ITP. Patient selection for eradication as an up-front treatment, analysis of the pathophysiology of platelet recovery after eradication and long-term effects should be investigated to make new treatment guidelines for newly diagnosed patients with ITP.