Epidemiological studies have suggested a lower risk of coronary heart disease (CHD) at higher intakes of fruit, vegetables, and whole grain. Whether this association is due to antioxidant vitamins or some other factors remains unclear. A study was conducted to investigate the relationship between the intake of antioxidant vitamins and CHD risk. A cohort study pooling 9 prospective studies that included information on intakes of vitamin E, carotenoids, and ascorbic acid, and that met specific criteria was carried out. During a 10-year follow up, 4647 major incident CHD events occurred in 293 172 subjects who were free of CHD at baseline. The dietary intake of antioxidant vitamins was only weakly related to a reduced CHD risk after adjustment for potential nondietary and dietary confounding factors. Compared with subjects in the lowest dietary intake quintiles for vitamins E and C, those in the highest intake quintiles had relative risks of CHD incidence of 0.84 (95% CI: 0.71, 1.00; P=0.17) and 1.23 (1.04, 1.45; P=0.07), respectively, and the relative risks for subjects in the highest intake quintiles for the various carotenoids varied from 0.90-0.99. Subjects with higher supplemental ascorbic acid intake had a lower CHD incidence. Compared with subjects who did not take supplemental ascorbic acid, those who took >700 mg supplemental ascorbic acid/day had a relative risk of CHD incidence of 0.75 (0.60, 0.93; P for trend <0.001). Supplemental vitamin E intake was not significantly related to reduced CHD risk. It is suggested that there is a reduced incidence of major CHD events with high supplemental ascorbic acid intakes. The risk reductions with high vitamin E or carotenoid intakes appear small.