Parents are warned that nearly a third of 12- to 17-year-olds in the United States have used an illicit drug in their life times, and teens are currently using drugs at younger ages. Of all the illicit drugs, marijuana is the most widely used. Consequently, the booklet focuses on the mental and behavioral problems associated with frequent, long-term marijuana use, notably adverse effects on memory, motivation, and attention span, as well as poor performance at school or work. Other substances and their adverse effects discussed are alcohol use, MDMA, methamphetamine, inhalants, prescription and over-the-counter drugs, and anabolic steroids. Signs and symptoms of drug use in general are then listed, followed by guidance for parents on how to interact and communicate with their teen children so as to prevent and counter their drug use. Guidance includes telling the child what you expect from their behavior regarding drugs inside and outside the home; setting rules and expectations; enforcing these rules consistently and fairly with consequences for violations; teaching children about identifying and avoiding risky situations; and educating children about messages that encourage drug use. Other advice to parents pertains to staying involved in their children's lives, what to do if children are caught with drugs or admit to having tried drugs, how to address peer pressure to use drugs, and how parents should tell their children if they themselves have used drugs.