Objective: To develop a reversed-phase HPLC method for the determination of swertiajaponin in the leaves of Lophatherum gracile. Method: Cosmosil 5 C18-ms-Ⅱ (4.6 mm×250 mm

5 μm) column was adopted with the mobile phase of acetonitrile-0.05% acetic acid solution (14:86); the flow rate was 1 mL ·min-1

and the detection wavelength was set at 350 nm. Result: The calibration curve was linear in the range of 0.3~5.0 μg (r=1.000 0); the average recovery was 100.2 %. Conclusion : The content of swertiajaponin in the leaves of L. gracile from 8 different sources was determined for the first time. The developed method is simple

accurate with good reproducibility.