Objective: The study was performed optimize the HPLC conditions and to establish a method to determine content of six effective components in the ≤1 000 Da extract of Erhuang decoction (baicalin

baicalein

palmatine

berberine

liquiritin

glycyrrhizic acid) simultaneously. Method: The RP-HPLC method used for the determination

on a chromatographic column of Diamonsil

C18 column (4.6 mm×250 mm

5 μm); with the was used mobile phase composed of acetonitrile:ammonium acetate solution (0.02 mol·L-1

acetic acid pH 4.0)

in gradient elution;the flow rate was fixed at 0.5 mL·min-1;the detection wavelength was set at 280

265

250 nm;the column temperature:was maintained at 25 ℃;the injection volume was 20 μL. Result: There is a good linear relationship between the chromatographic peak area and concentration of baicalin

baicalein

palmatine

berberine

liquiritin

glycyrrhizic acid in the linear range

and the recovery are all in the range of 95%-105%

with all the RSD of the recovery rate less than 2%. Conclusion: The method is rapid and simple for the content determination of six components content determination in the ≤1 000 Da extract of Erhuang decoction.