Lipid peroxide (LPO) in rat liver was detected by malondiadehyde (MDA) colorimetry. The effect of manganese, zircon and lithium alone on lipid peroxidation in rat liver was also studied. The results showed that manganese and zircon at the doses of (9.862-1.972) x 10(-4) and (0.1972-9.862) x 10(-5) nmol/L respectively decreased LPO in rat liver(P < 0.01). Lithium inhibited lipid peroxidation at the dose of (19.72-1.972) x 10(-4) nmol/L, and induced lipid peroxidation at higher concentration.