Iron is a vitally important element for the maintenance of health in living organisms. But, iron overload can be toxic. This study investigated the protective efficacy of quercetin against ferrous sulfate-induced oxidative stress, hepato-and nephrotoxicity in rats. There were five experimental groups (n = 7): Sham (distilled water, 1 ml/day for 14 days, i.p.), Quer (quercetin, 50 mg/kg/day for 14 days, i.p.), DMSO (dimethyl sulfoxide 1%, 1 ml i.p.), Fe (ferrous sulfate, 30 mg/kg/day for 14 days, i.p.), Fe+Quer (ferrous sulfate, 30 mg/kg/day for 14 days; quercetin, 50 mg/kg/day for 11 days from fourth day of ferrous sulfate injection). Blood, 24-h urine and tissue samples were collected at the end of experiment. Quercetin prevented ferrous sulfate-induced hepatotoxicity and nephrotoxicity as indicated by decreased activities of serum hepatic marker enzymes and decreased serum bilirubin concentration, higher levels of serum triglyceride, cholesterol, glucose, albumin and total protein, as well as higher creatinine clearance and lower fractional excretion of sodium. Besides, quercetin decreased malondialdehyde levels and histological damages in the liver and kidney of Fe group as compared with sham, DMSO and Quer groups. The protective effect of quercetin relies, at least partially, on its antioxidative effect which leads to decreased lipid peroxidation as well as iron-chelating property.