Abstract: Objective Compare the acute toxicity of different components of Radix et Rhizome Sophorae Tonkinensis and to provide experimental data for safe use in clinal. Methods Different components of Radix et Rhizome Sophorae Tonkinensis were administrated to KM mice.The MTD of all-components and the LD₅₀ of water extract, alcohol extract and total alkaloid extract of Radix et Rhizome Sophorae Tonkinensis were tested by the classical Methods of acute toxicity. The acute toxic symptoms were observed;the accumulated death number and the weight-changes of live mice were recorded. Results The MTD of all-components of Radix et Rhizome Sophorae Tonkinensis was 10.68g·kg^-1.The LD₅₀ of water extract,alcohol extract and total alkaloid extract of Radix et Rhizome Sophorae Tonkinensis were 17.469(15.450~19.701)g·kg^-1,27.135(24.869~29.622)g·kg^-1,13.399(12.016~14.899)g·kg^-1 in mice.Restlessness, breathlessness and convulsion were the main acute tixical symptoms. Conclusion The size order of acute toxicity of different components in Radix et Rhizome Sophorae Tonkinensis is total alkaloid extract>water extract >all-components>alcohol extract.The toxical components and toxical mechanism should be researched furtherly.

Key words: Radix et Rhizome Sophorae Tonkinensise, all-components, water extract, alcohol extract, total alkaloid extract, acute toxicity