The beneficial effect of estrogens and catecholestrogens against oxidative stress associated tissue injury has been observed in different experimental model. The administration of adriamycin (AD) has been shown to enhance oxidative stress in different tissues. The lack of estrogens during ovariectomy (OVX) also induces oxidative damage in several tissues. However, the antioxidant properties of estrogens and catecholestrogens administration have not been evaluated in erythrocytes and plasma from ovariectomized animals in presence or not of AD toxicity. We have assessed the antioxidant capacity of 17beta-estradiol (17beta) and catecholestrogens against oxidative stress in erythrocytes and plasma induced by OVX in control animals or AD-treated animals. We analyzed the level of lipid peroxides, carbonyl proteins and reduced glutathione (GSH) as well as glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities in plasma and erythrocytes. The results showed that AD, OVX and its combination increased lipid peroxides and carbonyl proteins, as well as reduced glutathione, superoxide dismutase and glutathione peroxidase activities in plasma and erythrocytes. The administration of 17beta and its metabolites (2- and 4-hydroxyestradiol) prevented all markers of oxidative stress induced by OVX in control and AD-treated animals. In conclusion, the administration of estrogens and cathecolestrogens counteract the oxidative stress in erythrocytes and plasma induced by OVX in presence or not toxic injury.