Objective:To develop a RP-HPLC method to determine the contents of protocatechuic acid

protocatechuic aldehyde and tyrosol in Yanlixiao Capsules. Methods: The samples was separated on a YWG C

18 column（4.6 mm×250 mm

10 μm）

using methanol-0.125% glacial acetic acid solution（10∶90）as the mobile phase with flow rate of 1 mL·min

-1 and detection at 275 nm. Results:The regression equation of protocatechuic acid was Y= 85 117x -15 733 （r= 0.999 5 ）

and the linear range was at 0.08 μg～0.56 μg. The regression equation of protocatechuic aldehyde was Y= 111 700x -37 980 （r= 0.999 8 ）

and the linear range was at 0.01 μg～0.07 μg. The regression equation of tyrosol was Y= 139 386x -29 146 （r= 0.999 6 ）

and the linear range was at 0.42 μg～2.94 μg. The average recovery of protocatechuic acid was 96.0%

RSD=2.37%（n=6）. The average recovery of protocatechuic aldehyde was 98.4%

RSD=2.05%（n=6）. The average recovery of tyrosol was 97.5%

RSD=1.93%（n=6）. Conclusion: The method is simple

rapid and accurate

and can be used for quality evaluation of Yanlixiao Capsules.