tough one to answer honestly. Personally I would sit them down and show it to them. Making sure you spouse (or significant other) is also there. Most likely it will be a friends. Get an At home drug test. Most hard drugs stay in the system up to 3 days.
You have a responsibility, if you find hard drugs (meth, cocaine, heroin, pills) anywhere near your kid, to do SOMETHING. Call your local police office (NOT 911), and ask them to recommend a good anti-drug program in your area.
1 - call the cops to take it, 2 - remove the door to their room, and 3 - sell all their luxuries (cell phone, computer, games, etc).
Why #3? Well, if they have the money to buy drugs, they have money to pay for their own luxuries. If they aren't buying drugs, they should be smart enough not to "hold" for somebody else. If they aren't smart enough for that, they should spend more time learning and less time on luxuries.
Been there, done that with one of my kids. The first time, we had a long hard talk with him and explained the legal consequences as well as the wrath of dad (me) that was coming. Apparently, that didn't do any good. The second time, he left the house in cuffs. He has since straightened out, a night in the local jail scared the crap out of him.
easy, i would put the drugs back in the pocket and call the police, then i would place them in a drug rehab program, then when they got out give them freedoms and rights one at a time until you can trust them again - realize this...if you find hard drugs on your kids, it is too late for the sit down talk-that is for pot.
Having been a kid who smoked pot, I would say confront them. And be above the situation.
Kid: You were snooping in my stuff! You: Seriously? hiding it in your pockets? sounds to me like you're more mad that you weren't smarter... now tell me when you started. After that, we need to discuss whether you need professional hel p to stop.
Note that I smacked em with comedy first. That sets them back on their heals. They already have it figured out how they will respond to normal confrontation. But dont brush it under the rug. How far you want to take it is up to you. But dont let it slide.
I agree with most of the answers, just remember that hard drugs are dangerous..something that will potentially kill your child. Make sure they take this as seriously as you do. If they don't take you seriously you need to scare them (jail maybe) or take something precious away from them until they can mature. Then try to get them involved in better people. Find out who they are hanging out with, and place them around good influences. Even if they hate it at first.
Having gone through this twice, I recommend getting your child into a drug rehab program as soon as possible. Do not expect them to tell you the truth, because they most likely won't. You may think you need to wait until it gets worse to do something, but believe me, it will only get worse and you don't want to go there. Take care.