Data were obtained in 1975 from two different groups, 310 industrial workers and 811 college students. The total sample of 1,121 adult respondents was composed of 517 males and 604 females; the racial composition was 954 white, 124 black, and 33 other. Each respondent was given a battery of tests that included a self-administered drug use questionnaire. Statistical analysis of data revealed alcohol was tried by nearly 99 percent of respondents. Of those who had tried alcohol, less than 6 percent considered themselves to be nonusers of alcoholic beverages, while 7 percent reported alcohol consumption on a daily basis. Tobacco products were tried by 77 percent of respondents; 35 percent of those who had tried tobacco products did not continue with tobacco consumption, while 39 percent reported consuming tobacco products on a daily basis. Marijuana was tried by 62 percent of respondents; 28 percent of those who had tried marijuana did not continue to use it, while 6 percent reported heavy marijuana use. Data justified the proposition that individual drug use was determined by an assessment of the drug's risk-benefit characteristics. 2 references and 2 tables