The Coptidis rhizoma is known for containing protoberberine alkaloids. Berberine, coptisine and palmatine are the major constituents of protoberberine alkaloids. The alkaloids were isolated and determined by forming complex compounds from Coptidis rhizoma in preparation I(Sam-Hwang-Sa-Sim-Tang) and II(Hwang-Ryen-Tang). For the determination of these alkaloids, a new spectrophotometric method was developed with a simple and selective sample clean-up using thiocyanatocobaltate[II] complex compound ion. The absorbance of alkaloidal complex compounds in l.2-dichloroethane solution was measured at 625 nm. Calibration curve for the alkaloids isolated from Coptidis rhizoma was linear over the concentration range of 0.2-0.3 mg/ml. The method was proved to be rapid, simple and reliable for the isolation and the determination of the alkaloids in Coptidis rhizoma preparation I and II.