Abstract: The purpose of the study was to investigate the pharmacokinetic behaviour of naringin and neohesperidin in rats after oral administration of different groups of flavanones,including the total flavanones of Zhishi extract (ZS),naringin (NA),neohesperidin (NHE),and naringin-neohesperidin (NA-NHE).Twenty-four Sprague-Dawley rats divided into four groups were treated with ZS (80 mg/kg),NA (32 mg/kg),NHE (27.2 mg/kg),and NA-NHE (NA 32 mg/kg and NHE 27.2 mg/kg),respectively.By using β-glucuronidase,free naringenin and hesperetin were obtained from the naringenin-glucronaide and hesperetin-glucronaide in plasma,and the aglycons in plasma were determined by LC-MS/MS.The pharmacokinetic parameters of naringenin and hesperetin in these groups were evaluated to indicate the pharmacokinetics of naringin and neohesperidin in these groups.Comparing the pharmacokinetic parameters of naringenin and hesperetin in the ZS group with the monomeric group，the AUC_0-t and c_max of naringenin and hesperetin increased significantly,while less difference with the NA-NHE group；the AUC_0-t and c_max of naringenin and hesperetin in the NA-NHE group also increased more than the monomeric group with the enhancive extension less than those of ZS group.The result showed that naringin and neohesperidin accelerated their absorption degrees with each other in accord with other components in the total flavanones of Zhishi extraction.