Objective: To develop a RP-HPLC method to determine the contents of oleanolic acid in Erzhi Pills. Method :The samples was separated on a Venusil X B P-C18 column ( 4.6 mm×250 mm

5 μm)

using methanol-0.4 % ammonium acetate solution (83 ∶17) as the mobile phase with flow rate of 1 mL ·min-1 and detection at 210 nm. The column temperature was maintained at 25 ℃. Result :the linear range of oleanolic acid was at 0.1004~1.807 μg (r=0.999 8). The average recovery of oleanolic acid was 99.7%

RSD 1.75%(n=6). Conclusion :The method is simple

accurate

and can be used for quality evaluation of Erzhi Pills.