Objective To observe the changes in the contents of matrine and oxymatrine after decocting flavescens for different times so as to provide the reference for the application of flavescens in compound formula.Methods HypersiL NH2(250 mm × 4.6 mm,5 μm)column was adopted.Ethanol-3% phosphoric acid(85∶7.5∶7.5)was taken as a mobile phase,the flow rate was 1.0 mL·min-1,and the detecting wavelength was 210 nm.Sample volume was 10 μL.Results While flavescens was decocted for longer time,matrine content increased and oxymatrine content did not change greatly.Conclusion In flavescens extraction,the time of decoction is not the chief factor to impact the transformation of matrine from oxymatrine.