Do you have a friend who is drinking alcohol or doing drugs? Are you worried about them? Are they doing reckless things, like driving under the influence of alcohol or drugs? Are they engaging in risky sexual behavior as a result of drugs or alcohol? Are their grades going down?
If your friend’s drinking makes you uncomfortable, you should let them know, and why. Let him or her know that you are worried about them. You should also try to make sure your friend stays safe. Don’t let them drink and drive, and certainly don’t ride with them if they do. Try to keep them from doing anything dangerous or embarrassing, like trying to walk home alone late at night, starting a fight or performing a silly prank.
Ask your friend if they need help, or suggest they go talk to someone who can help them, like a school counselor. If they don’t listen and you are still worried, it’s time to talk to your parents, or a counselor at school. As adults, they will know how to handle the situation, and make sure that your friend gets the help he or she needs.
You may feel weird about talking to an adult about this, but that's better than having regrets because you didn't talk to someone. Kids who drink or do drugs can really hurt themselves, or even die, due to risky behavior. If you care for your friend, do something.