The first section describes alcohol and drug use among students in Ontario. Although alcohol is the most widely-used drug (68 percent), tobacco and cannabis also have significant consumption rates (24 and 16 percent respectively), with use of other drugs ranging from eight percent for stimulants to about one percent for PCP. A small core uses drugs at potentially harmful levels. A preventive curriculum, linked to students' developmental stages and use patterns, should extend through all grade levels and be incorporated into a spectrum of subject areas. Informal school activities can supplement course materials. The goal of an early intervention program is to reduce alcohol and drug use and to mitigate associated problems. Students are encouraged to ask for assistance from designated teachers or counselors who then either counsel the student or refer the student to community addiction services. The counselors must be able to balance the student's confidentiality against the parent's right to know and to be involved in the recovery process. The school board must set clear guidelines for principals and teachers regarding disciplinary actions against alcohol and drug use on school property or school-sponsored events. The guidelines cover tobacco, alcohol, illicit drugs, and inhalants and include confiscation, suspension, and expulsion. School board committees comprised of trustees, staff, and community agency representatives can write policies modeled after the one in this guide, with modifications for local perspectives and values. 1 appendix.