Abstract: Morin,a naturally occurring flavonoid,has anti-inflammatory,anti-tumor,antioxidant effect,etc. Acute toxicity study of morin was performed in both sexes of ICR mice with at i.p.administration of morin at concentrations (230,280,330,390,450,530,630 mg/kg body weight,b.w.) with up and down method,through measuring half lethal dose LD₅₀,bodyweights,organ coefficients,peripheral blood index,serum biochemical index and pathology results for 14 days.The results demonstrated that high doses of morin had a certain acute toxicity in mice and the half lethal dose was 463.24 mg/kg with i.p.administration.Furthermore,the strength of toxicity was closely related with the dose of morin.

Key words: flavonoid, morin, acute toxicity, half lethal dose