Objective To investigate acute toxicity in mice and in vivo anti-inflammatory activity of aqueous extract from Asarum delavayi Franch. Methods The acute toxicity of the extracts in mice was determined by minimum lethal dose（MLD） combined with maximum tolerance dose（MTD）. Croton oil-induced mouse ear edema， carrageenan-induced rat toe edema， and cotton pellet granulation tissue hyperplasia were used to assess the in vivo anti-inflammatory effect of the extract. Results The acute toxicity results showed that ① the MLD of the aqueous extract from Asarum delavayi Franch was 15.12 g/kg and the MTD was 13.62g/kg. ② 3， 7， and 14 days after the administrations， there were no significant differences in the body weight among the vehicle group and various dose groups of the extract. ③ At the end of the experiment， the anatomical results suggested that the color of the kidney became lighter in parts of the animals after the administrations. The in vivo anti-inflammation results revealed that ① compared with the vehicle group， the aqueous extract（0.84g/kg， equal to 4.31g crude drug/kg） markedly reduced the ear edema of the mice. ② the extract（0.84g/kg， equal to 4.31g crude drug/kg） remarkably decreased carrageenan-induced rats toe swelling 60， 120， 240， 360 min after the sensitization. ③ the extract（0.42、 0.84g/kg） had no significant inhibitory effect on the cotton pellet granulation tissue hyperplasia. Conclusion The aqueous extract from Asarum delavayi Franch has a certain toxicity， and its toxic target organs are kidneys. The extract significantly suppresses acute inflammation such as croton oil-induced mouse ear edema and carrageenan-induced rat toe edema and not chronic inflammation like cotton pellet granulation tissue hyperplasia.