We evaluated the role of dietary vitamin C, vitamin E, and beta-carotene, as well as long-term vitamin E and beta-carotene supplementation, on the incidence of common cold episodes. A cohort of 21,796 male smokers was drawn from the Alpha-Tocopherol Beta-Carotene Cancer Prevention Study, which examined the effects of 50 mg per day vitamin E and 20 mg per day beta-carotene on lung cancer. Diet and background characteristics were recorded at the study entry, and subjects were queried three times per year on common cold episodes. We modeled the total number of colds during a 4-year follow-up period with Poisson regression, adjusting for covariates of dietary intake. Dietary vitamins C and E and beta-carotene had no meaningful association with common cold incidence. Long-term vitamin E and beta-carotene supplementation had no overall effect.Among subjects 65 years of age or older, the incidence of colds was slightly lower in the vitamin E group (RR = 0.95; 95% CI = 0.90-1.00); this reduction was greatest among older city dwellers who smoked fewer than 15 cigarettes per day (RR = 0.72; 95% CI = 0.62-0.83). In this male smoking population, vitamins C and E and beta-carotene had no overall association with the incidence of common cold episodes.