purpose To investigate the protective effect and character of dl-praeruptorin A(Pd-Ia)on focal cerebral ischemia in mice.Methods Transient focal cerebral ischemia in mice WaS induced by middle cerebral artery occlusion for 1.5 h.Pd-Ia was administered intraperitoneally either with multiple doses(1,5 and 10ms/ks)at 0.5 h before ischemia or single dose(5 ms/kg)at 0.5 h and 1 h before ischemic,the same time of ischemia,the same time of reperfusion,or 0.5 h and 1 h after reperfusion respectively.Neurological deficit score,infarct volume,brain edema,the activities of SOD and the contents of MDA were determined.Results Pretreatment with multiple doses(5 and 10 ms/ks)of Pd-Ia at 0.5 h before ischemia or single dose(5 mg/kg)of Pd-Ia at 0.5 h before ischemia,at the same time of ischemic,at the same time of reperfusion and 0.5 h after reperfusion significantly attenuated neurological deficit score,decreased infarct volume and alleviated brain edema,and the treatment at the time of reperfusion had the most marked effect.Pd-Ia(5 or 10 ms/ks)can significantly enhance the activities of SOD and lower the contents MDA.Conclusion dl-praeruptorin A has a neuroprotective effect on the injury in the acute phase of transient focal cerebral ischemia in mice,with optimal doses of 5 ms/ks and the optimal therapeutic time point of the same time of reperfusion.