Objective To observe the role and effect of allitridi to cerebral vasospasm following expe rimental subarachnoid hemorrhage.Methods The models of Japanese rabbits with symptomatic cerebral vasospasm were established by blood injection of twice cisternal magna.Via one side subclavian artery,allitridi was continuously infused by a mini pump.Results After continuous intra arterial infusion allitridi 2 d,the diameter of basilar artery in the treatment group increased more obviously than that before treatment ( P 0.05).There was marked ischemic pathological change in the structure of basilar artery and brain in the control group,however there was no obvious change in the treatment group.Conclusion Allitridi can improve acute cerebral vasospasm;and the continuous intra arterial infusion allitridi has preventive effects in delayed cerebral vasospasm.