Abstract: Berberine (1)and palmatine (2) in cortex phellodendron and Chinese patent medicines were determined by HPLC. The optimal composition of mobile phase CH₃COOEt—HCOOH—EtOH (15:3: 2) for HPLC separation of berberine and palmatine was successfully determined by using window diagram technique. Detection wavelength was 346nm. Flow rate: 1.5 mlimin. Calibration graphs for 1 and 2 were rectilinear for 0.06～0.32μg and 0.12～0.32μg respectively. The average recoveries of the two corresponding components were found to be over 96% and their coefficients of variation were below 5%.