Abstract: Objective To study the anti-inflammatory effect of aqueous extract from Toona sinensis and its mechanism.Methods The contents of prostaglandin EZ(PGE₂)and nitric oxide (NO)in seiwn and tissue were detected in rats with xylene-inducedear edema and carrageenin-induced pawedema and treated with gastric gavage of aqueous extract form Toona sinensis.Results Aqueous extmctfrom Toona sinensis showed amarked suppressive efffecton xylene-inducedear edema of mtsw ith the inhibition rotes of 33.85% and 46.98% at the doses of 0.5 and 1.5 g/kg.The Toona sinensis extract reduced the content of NO in seiwn at the dosage of 1.5 g/kg and the contents of NO,PGEZ in inflammatory tissue at the dosages of 0.5 and 1.5 g/kg.Conclusion Toona sinensis has a marked inhibitive effect on carrageenin-induced pawedem a in rots The effect may herelated to the inhibition of inflamm tatory mediators.