Abstract: BACKGROUND ＆ AIM: To study the embryonic and teratogenic toxicities of chitosan in rats during the period of organ formation. MATERIALS AND METHODS: Ninety pregnant SD rats were randomly divided into five groups with 18 rats in each, three chitosan dosage groups (50, 250, 1 000 mg/kg), one negative and one positive control group. Chitosan and normal saline was given by gavage to the treated groups and the negative control group for ten days during the period of organ formation (the 6th to 15th day of gestation),respectively. Rats in the positive control group received intraperitoneal cyclophosphamide (CP) on the 11th to 13th day of gestation at a daily dose of 7 mg/kg. The rats were sacrificed to examine the fetuses on the 20th day. RESULTS: The results showed that chitosan didn't produce significant effects on health, behavior, weight gain and reproductive parameters of pregnant rats and fetal growth, and didn't induce any teratogenic effect on the appearance, bones and bowels of the fetuses. CONCLUSION: Chitosan has no embryonic and teratogenic toxicity when used under 1 000 mg/kg.

Key words: chitosan, rats, embryo toxicity, teratogenicity