The sample comprised 9,330 secondary school students between the ages of 12 and 17. Data were collected by means of self-administered questionnaires with a range of multiple choice questions to intact classes and examined 10 categories of drugs. The results showed that alcohol and tobacco were the drugs most likely used for recreational or non-medical reasons and that marijuana and inhalants were the next most popular group used followed by hallucinogens, stimulants, and opiates. Between one- and two-fifths of all medication users reported use for other than health reasons. With the exception of inhalants, experience with each type of substance was more common among older students. The important trends in drug use associated with age should focus the attention of drug education and health programs on graduated intervention strategies across age groups and specific prevention programs for older students. 1 figure, 3 tables, and 11 references (Author abstract modified)