Abstract The costs of drug use to society and individuals include risk of chronic illnesses, such as HIV, hepatitis C and hepatitis B, and risk of accidental injury. Among accidents involving fatalities, drugs have been found in 15 to 20% of riders and drivers. Generally, the effectiveness of drug prevention programmers has tended to be assessed in relation to so-called ‘gateway’ drugs, such as alcohol, tobacco and marijuana, rather than specifically illicit drug use. The impact of drug prevention programmers on illicit drug use has not been adequately reviewed. Drug prevention in schools is a top priority and several well-designed studies have shown that prevention programs have the potential of reducing drug use in adolescents.