Vitexin was isolated from the leaves of Crataegus pinnatifida Bge. var major, and its pharmacokinetics and bioavailability were carried out via validated high-performance liquid chromatography (HPLC) method using hesperidin as internal standard in healthy rats after intravenous and oral administration at a dose of 10 mg/kg and 30 mg/kg, respectively. The pharmacokinetic parameters were calculated by both compartmental and non-compartmental approach. When intravenous administration was used, the elimination half-life (t(1/2 beta)), the mean residence (MRT0 -> t), the total body clearance (CL) were 46.01 +/- 0.810 min, 26.23 +/- 1.51 min and 0.031 +/- 0.035 L/kg.min. When oral administration was used, the t(max) and C-max were 15.82 +/- 0.172 min and 0.51 +/- 0.015 mu g/ml, the MRT0 -> t and CL were 60.41 +/- 5.41 min and 0.71 +/- 0.056 L/kg.min. The result showed that vitexin was rapidly eliminated and presented a low absolute bioavailability (F), 4.91 +/- 0.761%.