Objective:To establish the quality control methods for Xiakucao (Prunellae Spica)-Wubeizi (Acanthopanacis Cortex) bacteriostasis lotion, and study its bacteriostatic effects on common gynecological bacteria in vitro. MethodsThe content of gallic acid, the main active component of the lotion, was detected by high performance liquid chromatography (HPLC). The separation was performed on an Alltima C,18, column (4.6 mm*250 mm, 5 μm) by gradient elution with the mobile phases of 0.1% phosphoric acid dissolved methanol-0.1% phosphoric acid (21∶79) at a flow rate of 1.0 ml/min. The temperature of the column was 30 ℃ and the injection volume was 10 μl. The detection wavelength was 273 nm. The bacteriostatic effect of the lotion was verified by Kirby-Bauer susceptibility disk tests and bacteriostasis test.  Results:The linear curve of gallic acid fitted well in the range of 0.015 g/L-0.245 g/L (r=1). The average recovery was 95.46%. Bacteriostasis tests in vitro showed good bacteriostatic activity of Xiakucao-Wubeizi lotion against Staphylococcus aureus and Escherichia coli.  Conclusion:Determination of gallic acid in the lotion by HPLC is reliable for quality control. Bacteriostasis tests on common gynecological bacteria in vitro indicate that Xiakucao-Wubeizi lotion is an effective pudenda bacteriostasis agent.