A new HPLC method for the determination of puerarin in cerebral ischemia reperfusion rat plasma is introduced. Puerarin, the principal bioactive component of puerariae radix isoflavone, was extracted from plasma by methanol. The HPLC separation was then performed on a reversed-phase C18 column using water-acetonitrile (89:11, v/v) as eluting solvent system, and UV detection at 252 nm to measure the analyte with a limit of quantitation about 9.44 ng ml(-1). The calibration curve for puerarin was linear (r=0.9998) in the concentration range of 9.44-1208.00 ng ml(-1), both intra- and inter-day precision of the puerarin were determined and their coefficient of variation did not exceed 10%. The validated method has been successfully applied for pharmacokinetic studies of puerarin from rat plasma after intravenous administration of puerariae radix isoflavone. Another novel finding of this study was that the elimination rate of puerarin was significantly slower in the cerebral ischemia reperfusion rat than in the normal rat, judging by the pharmacokinetic parameters obtained. Since puerariae radix isoflavone was mainly administrated to the patients suffering from cerebralvascular diseases, the pharmacokinetic studies performed on the pathological animal models were suitable references for clinical application.