OBJECTIVE: To establish a high-performance liquid chromatography (HPLC) method for the determination of baicalin in Xiaoyanling Decoction. METHODS: HPLC method was used for determination. A Kromosil C18 column was used. The mobile phase consisted of MeOH-acid water (H(2)O:H(3)PO(4)=53:0.2) 40:60, and the detective wavelength was 277 nm. RESULTS: The content of baicalin in each Xiaoyanling Decoction sample was not less than 0.40 mg/ml (RSD<5%). CONCLUSION: The content of baicalin in Xiaoyanling Decoction is high and stable, and it can be used as the quality standard for Xiaoyanling Decoction.