[ Objective] The paper was to study the acute toxicity of Oxytropis Kansuensis Bunge on rats. [ Method ] Forty rats were randomly divided into two gToups： control group （distilled water） and trial group （water extract of 0. Kansuens/s） to carry out the acute toxicity experiment. The trial group was supplied with the maximum dose （6.0 g/ml,0.8 ml/20 g） twice per day for continuous 7 d. [Result] The maximal tolerance dose of rats to water extract of O. Kansuens/s was more than 480 g/kg. Feeding rats with O. Kansuens/s would not lead to the death of rats within short time （7 d） and no obvious macroscopic pathological changes in the viscera of rats could be seen in naked eyes. [Condusion] The study provided theoretical basis for full use of O. Kansuens/s resources.
