A simple and rapid method for determination of icariin (ICA) and its two metabolites, icaritin (ICT) and desmethylicaritin (DICT), by capillary zone electrophoresis has been developed and validated. Optimum separation of ICA, ICT, and DICT was obtained on 43.6 cm x 50 microm capillary using sodium tetraborate (30 mmol/L), monobasic sodium phosphate (50 mmol/L)-acetonitrile (50:50, v/v) (pH 10.0) as running buffer. Carbamazepine (CMP) was used as internal standard (IS). The temperature and voltage were optimized at 25 degrees C and 12 kV, respectively. The limit of detection of ICA was 1.0 mg/L (S/N = 3) by UV detection at 270 nm. The elaborated method was tested in vivo after administration of a single dose of 120 mg ICA/kg to healthy rats. Calculated parameters confirmed usefulness of the method in rat pharmacokinetic studies on ICA.