A new, simple and rapid capillary electrophoresis method was developed for the identification and quantitative determination of two medically active constituents-khellin and visnagin-in the extracts of Ammi visnaga fruits. Micellar electrochromatographic separation of khellin and visnagin was carried out using 10 mmol/l borate, 50 mmol/l sodium dodecylsulfate, 25% (v/v) acetonitrile at pH 9 as running buffer. Ammi visnaga fruits were extracted with methanol and the extracts were directly injected without any purification and pre-separation processes. Coumarin was used as internal standard for quantitation and the limits of detection for khellin and visnagin were 2.36 and 1.97 mug/ml, respectively using UV detection at 245 nm. (C) 2002 Elsevier Science B V. All rights reserved.