The purpose of this study was to investigate the relationship between mild degrees of liver dysfunction and spontaneous intracerebral hemorrhage (ICH) from the hemostatic standpoint. A detailed study of hemostatic systems was made in 462 patients with ICH. To compare ICH with the other cerebrovascular diseases, data from 120 patients with subarachnoid hemorrhage and 114 others with cerebral infarction were reviewed. At admission, the medical histories of the patients, including information about previous alcohol consumption, was taken, and blood samples were collected to perform the following studies: platelet count, fibrinogen level, prothrombin time, activated partial thromboplastin time, antithrombin III, plasminogen and alpha 2-antiplasmin activity, platelet aggregability, and liver function tests. The incidence of liver dysfunction and alcohol consumption in patients with ICH was significantly (P < 0.05) higher than in patients with subarachnoid hemorrhage and in those with cerebral infarction. Hematoma volume, mortality rate, and past alcohol consumption in patients with ICH significantly increased with worsening severity of liver dysfunction. Although almost all hemostatic parameters became worse with increasing severity of liver dysfunction, they changed within the normal limits. Platelet aggregability and alpha 2-antiplasmin activity in patients with liver dysfunction were remarkably deteriorated beyond normal limits. In conclusion, liver dysfunction associated with alcohol consumption appears to be an important factor in the deterioration of the clinical status of patients with ICH and may be one of the causative factors in the development of ICH. Although mildly impaired hemostatic systems may be partially responsible for these adverse effects of liver dysfunction on ICH, it seems probable that nonhemostatic mechanisms are attributed to the effects.