Objective: To separate and screen anti-inflammatory fraction of Isatidis Radix. Method: Membrane separation method was used to separate Isatidis Radix into different sections

their anti-inflammatory effects were evaluated by acetic acid-induced celiac capillary permeability and xylene-induced mouse ear swelling models in mice. Macroporous resin and ion exchange resin were used to further separate Isatidis Radix into different sections

and the anti inflammatory effects were evaluated by abouve mentioned models

finally

their chemical property was determined by color reactions. Result: The substance less than 1 000 in Isatidis Radix had a good inhibiting effect in mice era swelling model

the inhibition rate of swelling being 40.29%(P<0.05). The fraction absorbed by 732 cationic resin in the less than 1 000 substances could inhibit celiac capillary permeability andear swelling

the inhibiting rate being 17.76% and 28.20%

respectively (P<0.05). Color reactions showed that the fraction was composed of amino acids and alkaloids. Conclusion: The amino acids and alkaloids of Isatidis Radix could be the anti-inflammatory fraction.