The evaluation found that exposure to the curriculum was associated with a change in knowledge about drugs and drug use. More positive attitudes toward science at pretest predicted greater knowledge change, and students who knew less at the start showed a greater change in knowledge. Fifth-grade students showed a greater gain in knowledge than the fourth-graders. The theory of reasoned action, upon which the curriculum is based, posits that attitude and behavioral change flows from the acquisition of knowledge after the presentation of persuasive information. The evaluation findings thus suggest that the curriculum has promise as a component of the core curriculum and as a tool for the prevention of alcohol and drug use by youth. Suggestions are offered for further research in testing this theory. The curriculum used was "Brain Power!" it consisted of six learning modules on differences between legal and illegal drugs; major parts of the human brain and how they function; neurons and how they communicate through the process of neurotransmission; legal and illegal stimulants and their effects on the brain and body; the effects on the body, brain, and nervous system of alcohol, marijuana, and inhalants; and addiction as a disease that results from changes in the brain. The evaluation design assigned 112 students from 2 schools in the Washington, DC metropolitan region by classroom to treatment and control groups. Students in the treatment groups received the full curriculum, and those in the control group were not exposed to the curriculum. Students in both groups received identical surveys that contained questions on knowledge and attitudes about drugs before and after the implementation of the curriculum. 1 figure, 4 tables, and 51 references