Abstract: Objective To discuss the effect of different composition of Radix Bupleuri and Radix Bupleuri Scorzoneraefolli on mice's acute toxicity. Methods Respectively prepare the water extracted and alcohol extracted components of Radix Bupleuri and Radix Bupleuri Scorzoneraefolli, and compare the acute toxicity of different components in Radix Bupleuri and Radix Bupleuri Scorzoneraefolli on mice in accordance with classical acute toxicity test Methods, and the experimental datas are calculated MTD and MLD with the Kg body weight method, with the continuous administration and observa-tion for 14 days. Results The acute toxicity of different components in Radix Bupleuri and Radix Bupleuri Scorzoneraefolli on mice is: alcohol extracted components of Radix Bupleuri Scorzoneraefolli >alcohol extracted components of Radix Bupleuri >water extracted components of Radix Bupleuri Scorzoneraefolli >water extracted components of Radix Bupleuri. The water extracted components of Radix Bupleuri and Radix Bupleuri Scorzoneraefolli did not appear dead. Calculated by crude drug content, the MLD were respectively 181.6 g·kg^-1·d^-1 and 201.6 g·kg^-1·d^-1,which is equal to 1412.4 times and 1568.0 times of 70kg people's daily dried medicinal herb expenses. The alcohol extracted components of Radix Bupleur and Radix Bupleuri Scorzoneraefolli are unable to make LD50, the MTD were respectively 46.4 g·kg^-1·d^-1 and 75.2 g·kg^-1·d^-1,which is equal to 360.9 times and 584.9 times of 70kg people's daily dried medicinal herb expenses. Conclusion The toxicity of Radix Bupleuri Scor-zoneraefolli is bigger than the Radix Bupleur, and the toxicity of the alcohol extracted components is bigger than the water extracted components. There is some relevance between the content of Bupleurum saikosaponin and the toxicity, so we speculated that the Bupleurum saikosaponin may be the mainly toxical basis.

Key words: Radix Bupleuri and Radix Bupleuri Scorzoneraefolli, water extracted components, alcohol extracted components, mice, acute toxicity