Knowledge of the pineal, like that of other biological structures, has progressed from speculative to concrete information. A number of general roles have been suggested for the pineal gland over the years based on anatomical observations, studies of function and studies of biochemistry. We study the knowledges about the pineal before and after the successfully discovery of the melatonin by Lerner in 1958. Melatonin has recently been shown to have high antioxidative propies. Adriamycin, an antracyclinic antibiotic frequently used in quimiotepeutic treatments is highly toxic; it inhibits protein synthesis and provokes prooxidant effects. We tested the protective effects of melatonin against adriamycin toxicity in the rat. Our results demonstrate that oxidative damage induced by the antitumor drug, adriamycin, can be reduced by low pharmacological doses of melatonin.