Adriamycin is a potent anticancer agent, its clinical use isassociated with cardiotoxicity. The present study aimed to investigate thepossible protective role of the natural antioxidant silymarin onAdriamycin induced heart toxicity. The cardiotoxicity of Adriamycinwas manifested by elevateted cardiac enzymes (LDH & CPK) andincreased serum cholesterol and triglycerides. This toxicity wasassociated with severe histopathological changes in the form of highlyeosinophilic cytoplasm, degenerated myocardial fibers, interstitialoedema and mononuclear cellular infilteration. E/M examination of thecardiac muscle showed loss of cardiac myofilaments , swollen enlargedmitochondria and vaculation of the cytoplasm. Pretreatment withSilymarin ameliorated these pathological changes and decreased cardiacenzymes, serum cholesterol and TG levels.