Abstract: The purpose of the study was to verify the safety of compound traditional Chinese herb for alleviating sheep heat stress in sheep. According to Horn’s method, mice were given gavage at doses of 2 150, 4 640, 10 000, and 21 500 mg/kg body weight, and the lethal dose(LD₅₀) was calculated on the 14 th day after administration. In the maximum dose test, the experimental group was given 120 g/kg of normal saline by gavage, and the mice in the control group were given equal volume of normal saline by gavage. During the experiment, the mental state, breathing, presence or absence of special calls, hair smoothness, appetite, feces and death of the mice were observed and recorded every day. The mice in each group were weighed on an empty stomach at 0, 1, 2, 4, and 7 days after the injection, and the weight gain, feed intake, and weight growth rate of the mice were calculated. After the experiment, 4 mice in each group were randomly selected for blood sampling and blood biochemical indexes were detected. Then three mice were selected to be sacrificed by cervical dislocation, and then subjected to autopsy and observation. The coefficients of organs such as heart, liver, spleen, lung and kidney were counted. Meanwhile, the microstructure of the organs was observed by pathology. The results showed that when the dose of compound Chinese herb increased up to 21 500 mg/kg, no dead mice were observed and the LD₅₀＞21 500 mg/kg. There was no toxicity in mice at the maximum dose, and there were no significant differences in feed intake, body weight and body weight growth rate between experimental group and control group during the experiment（P＞0.05）. Although the hemoglobin concentration of the experimental group was higher than that of the control group（P＜0.05）, it was still within the normal range. In addition, conventional blood indexes such as red blood cell number, white blood cell number and platelet number, and serum biochemical indexes such as alanine aminotransferase activity, urea nitrogen and glucose concentration were not significantly different from control groups（P＞0.05）. In addition, no pathological changes were found in heart, liver, spleen, lung and kidney, and there was no significant difference in organ coefficients between the experimental group and the control group（P＞0.05）. From microscopic observation of organ, no drug-related pathological change of mice was found in experimental group. It indicated that the compound Chinese herb had no adverse reaction and was safe and reliable.