Dietary exposures being asessed in human populations include consumption of specific food groups and food items, such as meat, fruits and vegetables, ethnic dishes, and coffee; macronutrient and micronutrient intake, such as fat, vitamin A, carotene, vitamin C, folacin, and trace minerals; general nutritional status; anthropometry; biochemical indices, such as serum cholesterol and serum vitamin A; and storage and cooking practices. Cancers being studied include those of the colon, rectum, breast, esophagus, pharynx, oral cavity, lung, cervix, pancreas, stomach, kidney, larynx, and chorion. Case-control studies have been initiated in high risk areas with unusually high cancer mortality conceivably related to diet, and among migrants whose changing cancer rates appear related to new lifestyles, such as among Oriental-Americans. Selected cohorts with relevant dietary or biochemical data already collected, such as HANES I participants, are being followed. Data from HANES I and II are being analyzed to test specific hypotheses, such as the relationship of age at menarche to diet, and to provide descriptive information on U.S. dietary patterns, diet variation, and determinants of nutrient intake.