Abstract: Objective To discuss developmental toxicity and mechanism of aluminum.Methods Embryos of SD rat on day 9.5 of gestation were explanted and cultured in a whole-embryo culture system with exposure to Al₂(SO₄)₃ at Al³⁺ concentrations for 48 hrs in order to understand the developmental toxicity of aluminum.After 48hrs in culture,each viable embryo was evaluated by Brown's morphological scoring system.Yolk sac diameter,crown-rump length,head length and embryonic dry weight were measured.Results Dose-dependent decreases in embryonic development parameters and Brown's scores were observed with Al³⁺ concentration.Yolk sac diameter,dry weight,neural tube,heart and flexion scores decreased significantly at 1.2μg/ml(P<0.05).When exposure doses at ≥3.0μg/ml,the embryonic development and morphogenetic differentiation were obviously inhibited(P<0.05 or P<0.01),as well as the incidence of dysmorphogenesis significantly increased,including dorsiflexion and neural tube defects.Conclusion Aluminum was a developmental toxicant and dysmorphogent in rat.