Abstract: ObjectiveTo discuss the effect of saikosaponin d on mice's acute toxicity. MethodsMice's acute toxicities of different drug-delivery ways were tested respectively by the classic methods of acute toxicity. ResultsCaculated by saikosaponind, the MLD of ig is 770.47 mg·kg-1·d-1, the LD50 of ip is 62.338 mg·kg-1·d-1, and the 95% confidence interval is 53.703~70.966 mg·kg-1·d-1. The main acute toxicity symptoms of mice are negligent action, then unsteady gait, shortness of breath,drooping eyelids,hair rising, intermittent convulsion, neurological inhibition by ig.The signs of dead mice are neurological inhibition, and eventually to death by ip. The surviving mice's weight gainings are slower in 14 d observation period and compared with the control group, there is no signifi cant difference. By anatomical observation of death mice, there are no other obvious abnormalities except hepatic pathological changes.ConclusionThe acute toxicity of saikosaponin d is high, and we further confirmed that saikosaponin d is one of mainly toxical material composition of bupleurum.The "dose-timepoison"relationships of accumulated toxicity, biotransformation process in vivo and in vitro, and the position and mechanism of toxic effects are to be further studied.

Key words: saikosaponin d, mice, acute toxicity, LD50