The study examined a representative sample of 2,495 adult Spaniards, males and females, 18 years or older, selected by a multistage random strategy during 1989. Data were obtained through at-home interviews using a structured closed questionnaire. Alcohol had the highest lifetime prevalence of consumption, followed by cannabis, sedatives and sleeping pills, amphetamines, cocaine, inhalants, and heroin. Being male, young, separated or divorced, and unemployed were the main determinants of alcohol and drug use. A higher use of illicit drugs was also observed in the higher socioeconomic groups. Regular use of any drug was considered a risky health habit by more than 80 percent of the sample. The study concludes that the consumption of drugs and alcohol is a rather extended habit in Spain and describes prevention and control of alcohol use as a public health priority. Tables, notes, references