Objective: To study the anti-inflammatory activity of Huanglian Jiedu Tang(HLJDT) and its fractions as well as its material basis. Method: Xylene-induced ear-swelling and capillary permeability experiments were carried out to build the animal model

in order to determine the effective dose of HLJDT and then calculate the dose of each fractions of HLJDT. The animals were randomly divided into the blank group

the model group

the dexamethasone group

the HLJDT group

the HLJDT 50% alcohol-treated supernatant group

the water-treated precipitation group and the 50% alcohol-treated precipitation group

and administrated with drugs according to the traditional way for 3 days. Evans blue(EB) was intravenously injected 60 min later after the last administration

and then the mouse xylene induced inflammation experiment was immediately carried out. The anti-inflammatory effect of HLJDT and its fractions was researched with high performance liquid chromatography(HPLC)

and inter-group differences were compared. Result: Compared with the model group

dexamethasone

HLJDT

HLJDT 50% alcohol-treated supernatant and 50% alcohol-treated precipitation could effectively reduce the swelling degree and showed significant difference(P<0.01). The content of EB in the three groups mentioned above decreased to(11.8±1.8)

(23.4±3.8)

(25.2±3.2) ng·g-1

the swelling inhibition rates were 26.44%

29.89%

19.54%. HLJDT 50% alcohol-treated supernatant showed a more significant effect on anti-inflammatory than 50% alcohol-treated precipitation. Conclusion: HLJDT

HLJDT 50% alcohol-treated supernatant and 50% alcohol-treated precipitation could effectively reduce the swelling degree. On the basis of the result of HPLC

it can be inferred that the flavonoids interacted with alkaloids to reduce the side effect of alkaloids

increase the iridoids and showed a significant anti-inflammatory effect. Therefore

they are the effective anti-inflammatory fractions.