Respiratory infections are prevalent in the elderly, resulting in increased morbidity, mortality, and utilization of health care services. Contributing to the increased incidence of infection with age is the well-described decline in immune response, which has been correlated with patterns of illness in the elderly. For example, there are higher morbidity and mortality from cancer, pneumonia, and post-operative complications in those who have diminished, delayed-type hypersensitivity skin test responses. Nutritional status is an important determinant of immune function. We have shown in double-blind, placebo-controlled trials that vitamin E supplementation significantly improved immune response, including DTH and response to vaccines. Furthermore, subjects receiving vitamin E in the 6-month trial had a 30% lower incidence of infectious diseases. That study, however, was not powered to demonstrate statistical significance, and the infections were self-reported. To overcome these limitations, we conducted a double-blind, placebo-controlled trial to determine the effect of one-year supplementation with 200 IU/day vitamin E on the incidence and duration of respiratory infections in 617 elderly nursing home residents. The results of this clinical trial show that vitamin E supplementation significantly reduces the incidence rate of common colds and the number of subjects who acquire a cold among elderly nursing home residents. A nonsignificant reduction in the duration of colds was also observed. Because of the high rate and more severe morbidity associated with common colds in this age group, these findings have important implications for the well being of the elderly as well as for the economic burden associated with their care.