<jats:title>Abstract</jats:title><jats:p>Capillary zone electrophoretic (CZE) separation of pharmacologically active alkaloids, matrine, sophocarpine, sophoridine, oxymatrine, and oxysophocarpine, was systematically optimized, and their contents in different parts of <jats:italic>Sophora</jats:italic> species were quantitatively determined within 16 min under the following optimized conditions: 0.04 mol/L citrate buffer system at pH 4.5, applied voltage 30 kV, capillary temperature 25°C, and diode array detection at 201 nm. The recoveries are from 90 to 108%, with repeatability ranging from 0.7 to 4.2% (relative standard deviation) and the detection limits ranging from 0.032 to 0.070 mg/mL (signal to noise ratio=3). The proposed CZE method is suitable for routine analysis and quality control of herbal medicines that contain these alkaloids. © 2001 John Wiley & Sons, Inc. J Micro Sep 13: 221–226, 2001