Abstract: An acute toxicity test of Eprinomectin in situ gel injection on mice was taken to evaluate its safety by simplified Karber's method. The dosage and grouping were determined based on the minimum lethal dose（LD₁₀₀） and the maximum tolerated dose（LD₀） in preliminary experiment. The mice were administered with Eprinomectin in situ gel injection and observed seven days. The number of deaths was recorded for calculating the LD₅₀（lethal dose 50%） and the 95% confidence limit. The results showed that the acute toxicity LD₅₀ of Eprinomectin in situ gel injection on mice was 5.903 g/kg,95% confidence limit ranges was from 5.105 3~6.415 0 g/kg. It indicated that the Eprinomectin in situ gel injection was non-toxic substances according to chemically drug classification.

Key words: Eprinomectin in situ gel injection, LD₅₀, mice, acute toxicity