Object To isolate and identify the four active constituents, chrysophanol, emodin, rhaponticin and rhein in rhubarb Methods Micellar electrokinetic capillary chromatography (MECC) with a buffer solution of 5 mmol/L H 3BO 3 NaOH containing 20 mmol/L of sodium deoxycholate (SDC) (pH=10) was used for their separation at a voltage of 17 kv Results The four active constituents were completely separated within 5 min Conclusion This method was found to be simple and rapid and gave satisfactory results