Possible protective effects of a methanolic extract of Viscum album (VA) and quercetin (QE) against cyclophosphamide (CP) induced cardiotoxicity, urotoxicity and genotoxicity in mice were evaluated. Mice were administered orally VA (250 mg/kg/day) and QE (50 mg/kg/day) for 10 days alone or in combination with CP. After the same doses of VA and QE given for 7 days, rats were intraperitoneally administered CP (40 mg/kg) on days 8 and 9 of the experiment. Cardiotoxic, urotoxic and genotoxic effects were examined in serum, heart, bladder and bone marrow. Significant decreases in the levels of antioxidant enzymes (superoxide dismutase, catalase and glutathione peroxidase), glutathione-S-transferases, reduced glutathione and mitotic index were observed. QE completely and VA partly ameliorated almost of all the examined parameters when given together with CP. Higher total nitrate/nitrite levels were observed in the myocardial tissue treated with QE and VA in combination with CP. In addition, the pre-treatment with VA and QE together with CP significantly decreased chromosome aberrations and aberrant cells compared to CP alone. Results from the current study suggest that QE and VA supplementation attenuates CP induced cardiotoxicity, urotoxicity and genotoxicity through a mechanism related to their ability to decrease oxidative stress and inflammation, and at least in part to its protective effects on the cardiovascular system. In addition, VA and QE may play a role in reducing cytogenotoxicity induced by anti-neoplastic drugs during cancer chemotherapy.