A simple and rapid method for the simultaneous determination of eight quaternary alkaloids (coptisine, berberine, epiberberine, palmarine, columbamine, berberastine, jatrorrhizine and magnoflorine) in coptis rhizome by capillary electrophoresis was developed. A buffer solution composed of 85% 0.1 M sodium acetate solution and 15% methanol was found to be the most suitable electrolyte for this separation, whereby the levels of the eight quaternary alkaloids in the crude drug Coptidis Rhizoma could be easily determined. © 1992.