Abstract: ObjectiveTo explore the effects ofmanganese(Mn) on lip idperoxidation and contents of iron and zinc in the lung and liver of mice and the mechanism of manganese toxicity.MethodsAfter single exposure to MnCl2(100mg/kg body weight) via i p.in 30 mice, the activity of aspartate am inotransferase (AST),alanine am inotransferase (ALT) and lacatate dehydrogenase(LDH)were deteunined at 1st, 2rd, 4th and 7th day The lipid peroxidation(LPO)and concentrations of Mn, calcium (Ca),zinc (Zn) and iron (Fe) in the lung and liver of the mice were also measured.ResultsThe activity of AST, ALT, LDH, LPO and concentrations of Mn were achieved peak value after one day of Mn administration (P<0.05) and then decreased significantly.Concentrations of Ca in the lung and liver in Mn exposed groups were significantly higher than those of in controls and achieved peak value two days after Mn administration(P<0.05),but concentrations of Fe and Zn were significantly decreased(P<0.05).Obvious toxicity of Mn to lung and liver of mice was observed.ConclusionLipid peroxidation and metalbolic obstacle of Ca, Zn and Fe may be inportant mechanism of lung and liver injury caused by Mn in mice.