OBJECTIVE:To established a method for determining matrine and oxymatrine in human plasma.METHODS:The plasma was extracted with chloroform-n-butyl alcohol(98∶2) after basification and purified with neutral alumina solid-phase extraction.Then it was eluted with a Lichrosorb-NH2 column and CH3CN-CH3CH2OH-H3PO4(80∶10∶8),detected at ? 220nm.RESULTS:The linear range was 1.25mg~40mg/L and the limit of detection was 0.1mg/L(S/N=2).The average recoveries of matrine and oxymatrine were 106.96% and 105.04%,respectively.RSDs of within-day and between-day were lower than 13% and 7% respectively.CONCLUSION:The present study provides a simple and reliable method for determining concentrations of matrine and oxymatrine in human plasma.