To compare the efficacy and safety of two antiplatelet regimens, ticlopidine alone (200 mg daily) and ticlopidine (100 mg daily) plus aspirin (81 mg daily), in patients with ischemic stroke from the Tokai district of Japan.A randomized comparative study was performed from April 1992 until December 1995, with follow-up for an average of 1.59 years (maximum: 3 years). Statistical analysis was done on 270 eligible patients (138 treated with ticlopidine alone and 132 treated with ticlopidine plus aspirin).A total of 276 patients who had cerebral infarction within the previous 1 to 6 months, or one or more transient ischemic attacks within the previous 3 months.The incidence of ischemic and hemorrhagic stroke, myocardial infarction, and other vascular events was 10.1% (n = 14) in the ticlopidine group and 9.8% (n = 13) in the ticlopidine plus aspirin group, showing no significant difference (p = 0.933). There was also no significant difference in the event-free rate between the two groups (p = 0.5003, Kaplan-Meier analysis and log-rank test). Regarding serious adverse reactions, neutropenia occurred in one patient from the ticlopidine group, while gastric ulcer and thrombocytopenia occurred in one patient each from the ticlopidine plus aspirin group.We conclude that both antiplatelet regimens are comparable in efficacy and safety for preventing the recurrence of ischemic stroke.