Abstract: OBJECTIVE To observe the acute and chronic toxicity of Yigu oral solution. METHODS Tests of acute toxicity: 40 ICR mice were randomly divided into two groups, the control group and the drug test group. The maximum tolerable dosage (MTD) of Yigu oral solution were determined by i.g. administration in mice. Tests of chronic toxicity: 80 SD rats were randomly divided into four groups: high, middle, and low dose(80, 40, 20 g·kg^-1) of Yigu oral solution group as well as the control group. Yigu oral solution was continuously administered intragastrically for 12 weeks, once per day. The growth condition, blood routine test, blood biochemical indexes and histopathological changes of rats were measured immediately at the terminal of experiment and 28 days after the terminal of experiment. RESULTS The MTD of Yigu oral solution via i.g. administration was 358.852 g·kg^-1 in mice. It was equivalent to 287.08 times of the dosage used in clinic. After rats were administered consecutively for 12 weeks, the level of ALP and ALB in high dose group were lower than the control goup (P<0.05). Twenty-eight days after the terminal of experiment, the body weight of rats, food consumption, behavioral activity, hematological parameters as well as viscera index of important organs were normal. No obvious histopathologic changes of important organs were found. CONCLUSION Under this experimental condition, Yigu oral solution is safe and nontoxicity.