San Marcos Prevention Coalition | Working together for alcohol and drug free san marcos youth Working together for alcohol and drug free san marcos youth Our Mission The San Marcos Prevention Coalition mission is to reduce youth alcohol and drug use and advocate for safe and healthy neighborhoods by improving environmental norms and community policies and enhancing efforts to promote and deliver effective substance abuse prevention. Upcoming Events Did you know. The simplest and most costeffective way to lower the human and societal costs of drug abuse is to PREVENT it in the first place Office of National Drug Control Policy Youth Prevention Services Watch the 2019 Red Ribbon Week City Proclamation Video. Click here to view a directory of prevention programs.