Abstract: Objective To observe the inhibitory effect of lithium chloride(LiCl)on macrophage function.Methods Phagocytic function,abilities to produce nitrous oxide and hydrogen peroxide of macrophage in mice were dete rmined 20 days after they were admin istered continuously with LiCl at the doses of 0.4,0.6,and 1.2 mg/kg·bw.Results Compared with the control group,phagocytic function of macrophage of LCil treated mice was inhibited significantly with inhibition rates of 27.7%,40.2%,and 43.8%,respectively in a dose-response pattern.The ability of microphage to produce nitrous oxide was significantly inhibited also(42.36±14.22,25.64±12.42,37.82±13.48 μmol/L for the LiCl dose of 0.4,0.6,1.2 mg/kg·bw,respectively)compared with 54.21?12.55 μmol/L of the control group.The ability of microphage to produce O-2 was obvio usly inhibited by LiCl in a dose-response manner(P<0.05).The ability of microphage to produce hydrogen peroxide was inhibited only at a dose of 1.2 mg/kg·bw of LiCl with a significant difference compared with the control guoup.Conclusion At doses of 0.4,0.6,and 1.2 mg/kg·bw,LiCl couldinhib it the phago cytic fumction of microphage and the production of biologicalm olecules such as nitrous oxide,O-2,and hydrogen peroxide.