A simple RP-HPLC method was developed for the determination of jatrorrhizine, palmatine, corlumidine, bulbocapnine, bicuculline, protopine and tetrahydropalmatine in Corydalis decumbens and its preparations. Using chemically bonded ODS silical gel as the stationary phase, a mixture of acetonitrile and phosphate-triethylamine buffer (32:68) (pH 2.0), a mixture of acetonitrile, methanol and phosphate-triethylamine buffer (pH 3.0) (10:15:75) were suitable mobile phases for the separation of quaternary alkaloids and tertiary alkaloids, respectively. © 1994.