The purpose of this study was to investigate the relationship between dietary antioxidant intake and the risk of subarachnoid hemorrhage (SAH) in a case-control study. An antioxidant intake score was calculated for individual values for each food group (soy products, green yellow-vegetables, fruits, boiled rice and tea) collected by a self-administered food frequency questionnaire. Incident SAH cases (n=201) were identified and individually matched for age (+/-2 years) and gender to community (n=201) controls from April 1992 to March 1997. The antioxidant intake score was inversely associated with the risk of SAH, even after adjusting for confounding factors (lowest vs highest score adjusted odds ratio, 0.54; 95% confidence interval, 0.30-0.99). These findings suggest that the development of SAH may be reduced by the frequent intake of various antioxidants in the diet. Prospective studies are needed to confirm the relationship of dietary antioxidants to SAH risk in Japanese men and women.