The epidemiologic data do not support a strong role for vitamin C in reducing risk of coronary disease. The evidence supporting a protective effect for the family of dietary carotenoids is stronger, but any important protective effect attributable to the specific supplementation of beta-carotene can be excluded. Conversely, results from observational and experimental studies consistently support an effect of vitamin E supplementation on reducing risk of coronary heart disease. The evidence suggests that the major effect, if any, is found at supplemental intake levels at or greater than 100 IU/d. If confirmed in further trials, the net benefit of vitamin E supplementation among populations with existing coronary disease may be substantial, although the current available evidence is insufficient to warrant a change in public policy recommendations.