QUERCETIN (QTN); 3,5,7,3',4'-pentahydroxy flavone is a well known phenolic compound widely present in the plant kingdom. This study investigates the potential of QTN to protect the hepatic, myocardial and renal tissues against global reperfusion injury induced by γ-irradiation. The study was performed in Sprage Dawlly rats that were administered during 7 days with QTN (50 mg/ kg body wt), before or after exposure to 6 Gy γ-rays with appropriate controls. The irradiation data revealed significant elevation in plasma malondialdehyde (MDA) and conjugated dienes (CD) accompanied by reduced levels of total glutathione (GSH) and nitric oxide (NO). In addition, reduced activity of glutathione reductase (GR) and increased lactate dehydrogenase (LDH) activity were determined in tissue homogenates of liver, heart and kidney due to radiation damage when compared with respective control values. Treatment with QTN either before or after radiation-exposure improved organs function and reduced the severity of liver, heart and kidney injuries reflected by the lower concentrations of lipid peroxidation and the pro-inflammatory and tissue damaging LDH-indicator. In addition, improvement in the oxidative-stress' indicators confirms the therapeutic and protection effectiveness of QTN. These effects were linked to peroxyl-radical trapping capacity of QTN, which quenches free radicals induced by exposure of rats to γ-rays, thus improving regeneration of the biological tissues. It may be concluded that QTN is effective in this model of organs injury and cell damage and could become useful supplement in the treatment of liver, heart and kidney inflammatory status and oxidative stress.