There is a world of information out there on how to prevent underage drinking and drug abuse, as well as how to handle the situation if you believe your child might be using.
Start with the Partnership for Drug-Free Kids, which offers information and resources in both English and Spanish.
For science information on drug and alcohol abuse, look to the National Institute of Drug Abuse. There is also a wealth of information on underage drinking and the effects of alcohol on teens at the National Institute on Alcohol Abuse and Alcoholism.
Do you want information to provide your teen? The National Institute of Drug Abuse has a website designed just for teens.