This Department of Health and Human Services, Substance Abuse and Mental Health Services Administration report presents national information from the 2000 National Household Survey on Drug Abuse (NHSDA) on the rates of use, numbers of users, and other measures related to illicit drugs, alcohol, cigarettes, and other forms of tobacco. The NHSDA surveys those noninstitutionalized civilians in the United States aged 12 years or older. The scope of the problem estimated that 14 million Americans reported using an illicit drug in the month prior to the interview in 2000, more than a quarter of young people aged 12 to 20 in 2000 had used alcohol in the month prior to the interview, and on an average day, 5,556 persons tried marijuana for the first time and 3,737 begin smoking cigarettes on a daily basis. The 2000 report addressed mainly changes in rates of drug use between 1999 and 2000 and the differences in patterns of use among various demographic and geographic subgroups of the United States populations. Highlighted findings were presented on illicit drug use, alcohol use, tobacco use, trends in initiation of substance use (incidence), and prevention-related data. Two general conclusions were stated. First, substance use rates were generally level or declining between 1999 and 2000, and second, use and abuse of licit and illicit substances in the U.S. remains a major problem affecting a large proportion of the population.