Evidence is increasing that oxidation of low-density lipoprotein cholesterol may be instrumental in atherogenesis. As a result, a number of studies have been undertaken to evaluate the effects of antioxidant vitamins, beta carotene, selenium, and monounsaturated fat on coronary artery disease. Results in many instances have been promising, particularly in the case of vitamin E supplements. Studies of pro-oxidants, such as iron and copper, are inconclusive at this time, and a trial to assess the value of probucol in hypercholesterolemic patients is currently under way.