Objective To observe the effect of compound Epi medium injection(CEI )on focal cerebral ischemia in rats.Methods Sixty Sprague -Dawsley rats were ran domly allocated to six groups:mimic operation group(n=10),model group(n=10),tetramethylpyrazine injection gro up(n=10),CEI groups(treated with large -,moderate -and small -dose of CEI respectively).Focal cerebral ischemia in rats was induced by occlusion of right middle cerebral artery and the effects of CEI on plasm a levels of TXA 2 and PGI 2 ,platelet aggregation ,SOD and MDA a ctivities and infarct size of brain were observed.Results CEI could increase PGI 2 level in plasma,lower platelet aggregation rate,increase SOD activity,decrease TXA 2 level and MDA content and lessen the i nfarct size of brain.Conclusion CEI can keep the balance of TXA 2 -PGI 2 ,inhibit platelet aggregation and i ncrease the volume of cerebral blood flow.Meanwhile,it can also elimi-nate oxygen free radicals,improve cerebral function and relie ve ischemic damage induced by acute c erebral infarction.