ObJective: To study the change of the content of active ingredient in Chinese material medicine. Method: Seven kinds of different compatibility of Dachengqi dceoctions were made when Rhei Radix et Rhizoma was decocted with other three drugs (Magnoliae Officinalis Cortex

Aurantii Fructus Immaturus and Natrii Sulfas)

then the quantitative analysis of naringin and hesperidin was determined by HPLC. Result: The flavonoid content was influenced by different compatibility of Dachengqi decoction. The contents of naringin and hesperidin were 4.45% and 1.16% in the traditional decoction

of which higher than those of in other decoctions. The linear range of naringin and hesperidin showed a good correlation from 0.168 5 to 1.684 8 μg(r=0.999 8)

and from 0.022 8 to 0.228 0 μg(r=0.999 5)

respectively. Their average recoveries were 98.85%(RSD=1.36%) and 98.20%(RSD=2.26%)

respectively. Conclusion: The flavonoid content was increased when all drugs were decocted. The HPLC method was well specified for determinantion of the contents of naringin and hesperidin

which could be applied to the quality control and active ingredient determination of compatibility of Dachengqi decoction.