Objective To improve the quality standard of Xiaoyan Jiedu pill,and provide the optimum and controllable quality standards for the product. Methods TLC was used to identificate the Lonicerae Japonicae Flos,Saposhnikoviae Radix,Forsythiae Fructus,and Glycyrrhizae Radix. HPLC was used to determine the content of caffeic acid. The column was DIKMA Diamonsil C18( 250 mm × 4. 6 mm,5μm). The mobile phase was methanol-phosphate buffered saline( 23 ∶ 77). The detection wavelength was 323 nm. The column temperature ...