ObjectiveTo establish a HPLC-MS method to simultaneously determine the contents of gentiopicroside, liquiritin, rosmarinic acid and harpagoside in Fuzhengpingxiao capsule. MethodsThe chromatographic separation was performed on a Agilent Eclipse plus C18 column (250 mm×4.6 mm, 5 μm) with a mobile phase of acetonitrile(A)-0.1% methanoic acid(B) (0-30 min, 15%A-40%A), eluted at a flow rate of 1.0 ml/min and with a split ratio of 31. Negative ionization and selected ion monitoring(SIM) mode on Mass were selected. ResultsThe limit of quantitation(LOQ) values of gentiopicroside, liquiritin, rosmarinic acid and harpagoside were 5.73, 6.37, 6.50, and 6.46 ng/ml, and the limit of detection(LOD) values were 0.46, 0.32, 0.33 and 0.32 ng/ml, respectively. Good linearity (r>0.999 0) was obtained over the investigated concentration ranges. Reproducibility was evaluated by intra- and inter-day assays, and RSD values were below 2%. The average recoveries of the 4 compounds were within the range of 98%-102%. ConclusionWe have established a rapid and efficient HPLC-MS method for determination of 4 constituents in Fuzhengpingxiao capsule: gentiopicroside, liquiritin, rosmarinic acid and harpagoside.