In this paper the relation between alcohol intake assessed on the 1980 Nurses' Health Study questionnaire and subsequent risk of major chronic diseases in this cohort of middle-aged is reviewed. An increased risk of breast cancer among women consuming as little as 3 to 9 drinks per weeks is consistent with findings in other prospective studies. This same level of intake is inversely related to coronary heart disease and ischemic stroke; however, the risk of hemorrhagic stroke is increased. Alcohol intake is also inversely related to a risk of gall stones and noninsulin-dependent diabetes mellitus in this cohort.