Reactive oxygen species (ROS) are continuously produced in aerobic organisms. Overproduction of ROS is known to play a crucial role in the pathogenesis of many cardiovascular diseases, including atherosclerosis and hypertension. Superoxide dismutase (SOD) and catalase (CAT) play critical roles on the removal of excess ROS. In the present study, we investigated the antioxidant activity of cyanidins from ogapy (Acanthopanax divaricatus var. albeofructus, ADA) fruits against oxidative stress in hydrogen peroxide ($H_2O_2$)-pretreated U937 macrophages, and explored the plausibility of the therapeutic effect of cyanidins on atherosclerosis. As a result, $H_2O_2$ generation and lipid peroxidation induced by $H_2O_2$-pretreatment was decreased by the treatment of cyanidins in U937 macrophages. In addition, increased activity of SOD and CAT was shown in $H_2O_2$-pretreated cells when treated with cyanidins. Overall, the results obtained in this study showed that cyanidin 3-galactoside and cyanidin 3-lathyroside from ADA fruits could protect macrophages against the damaging effects of $H_2O_2$ treatment.