Abstract: OBJECTIVE：To understand the acute toxicity and genotoxicity of Chionanthus retusus leaves. METHODS：Acute oral toxicity test was performed with a dose of 10 g/kg which was administered orally once and observe for two weeks. For the bacterial reverting mutation test，five doses were set up. spontaneous reverting，solvent control and positive control were set up. After inoculation，the cells were cultured at 37 ℃ for 48 hours，and the number of reverting colonies in each dish was counted. Both the mammalian red blood cell micronucleus test and the chromosome aberration test of mouse spermatocytes were set up with three dose groups of 1 250，2 500 and 5 000 mg/kg. At the same time，a solvent control group and a positive control group were set up. The test substance was administered by gavage. The mammalian red blood cell micronucleus test adopted the 30-hour test substance delivery method，and femoral bone marrow smears were collected. Incidence of micronuclei in polychromatic erythrocytes in the smear was determined. For the chromosome aberration test of mouse spermatocytes， test subjects were dosed continuously for 5 days. On the 13th day，bilateral testicular smears were taken to observe the types and corresponding quantities of chromosome aberrations in the smears. RESULTS：The oral LD₅₀ of Chionanthus retusus leaves on both male and female mice was greater than 10 g/kg，and it showed negative reactions in the bacterial reverse mutation test，mammalian red blood cell micronucleus test and mouse spermatocyte chromosomal aberration test. CONCLUSION：Under the conditions of this experiment，Chionanthus retusus leaves were non-toxic and did not show genotoxicity.

Key words: Chionanthus retusus leaves, acute toxicity, genetic toxicity, mouse