To determine clininal features of Japanese patients who developed intracerebral hemorrhage (ICH) while receiving antithrombotic agents, we performed a retrospective study based on the medical records of 947 patients with nontraumatic ICH from 11 institutes between 1999 and 2003. On the treatment with antithrombotic therapy were 31.6% of the patients (20.7% of patients taking antiplatelets, 8.1% taking warfarin, and 2.5% taking both). The proportion of cerebellar hemorrhage to total ICH increased from 5% of the patients without antithrombotics to 9% of those on antithrombotic therapy (p=0.046). Advanced age (p<0.0001), male gender (p=0.0001), diabetes mellitus (p=0.045), history of ischemic stroke (p<0.0001), heart diseases (p<0.0001), and hematoma growth on computed tomography during the initial 24 hours (p=0.0043) were more frequent in ICH patients taking antithrombotic agents than in the others.
