Objective To explore the effect and mechanism of taking sibelium long term for treatment and preventing the attack again of cerebral infartcion.Methods 339 patients with cerebral infarction were divided into 2 groups randomly,namely preventing group(120 cases) and control group(119 cases).The basic treatment in the two groups are the same.The preventing group was taken siblium 10 mg once every evening,at least 6 months.To observe the clinical effect in 1 month and the rate of attack again in 1 year.The two groups were measured on hemorrheology,blood lipid and platelet aggregation rate before and after treatment one year.Results After treatment one month,the significant effective rate in sibelium preventing group is 80%,the total effective rate is 98.3%,but the control group is 54.6% and 74.8%(all P