Abstract: Objective To discuss the effect of total Bupleurum Saponin extracts on rat's acute toxicity. Methods Make the study on rat's acute toxicity of thetotal Bupleurum Saponin extracts in accordance with classical acute toxicity test methods. Results Caculated by totalsaikosaponin, the LD50 is 2 255.6 mg·kg^-1·d^-1, and the 95% confidence interval is 2 057.2～2 452.9 mg·kg^-1·d^-1.The main acute toxicity symptoms of dead rat are negligent action,then arising from unsteady gait, abdominal lying sleeping, rapid heart rate, shortness of breath, continuous convulsions, neurological in hibition, and eventually to death. The surviving rat's weight gainings are slow in 14d observation period and there are no other obvious abnormalities. Conclusion The total Bupleurum Saponin extracts can induce all rats to be dead, and its toxicity on rats is smaller than the mice. The toxical location and mechanism are all to be further studied.

Key words: total Bupleurum Saponin extracts, rats, acute toxicity