Abstract： Objective　To obseve the effect of puerarin on cerebral inducible nitric oxide synthase（iNOS) during global cerebral ischemia and reperfusion．Methods　The rats were randomly divided into three groups：control group（only exposed anatomically without cerebral ischemia and reperfusion）；normal saline（NS） group（global cerebral ischemia and reperfusion with administration of NS through abdomen）；puerarin group（global cerebral ischemia and reperfusion with administration of puerarin through abdomen）．Global cerebral ischemia and reperfusion was induced by means of Pulsinellis four blood vessel occlusion model．iNOS in rat brain was measured with immuno-histochemical staining method．Results　As the time of reperfusion lasted，the level of iNOS in NS group declined markedly（P＜0.05)，and the longer the period of reperfusion，the more the difference（P＜0.01)between the NS group and the control group；whereas iNOS in puerarin group increased gradually， the level of iNOS of puerarin group was much higher than that of NS group at 24h reperfusion（P＜0.05)．Conclusion　Cerebral iNOS system can be markedly damaged after global cerebral ischemia and reperfusion，puerarin can lessen this damage．