What will you do if you caught your teen smoking?

First of all, don't yell and just try and understand. Talking it out and listening is always the the best thing to do. Next step depends on how old is the 'teen'. If he/she is already around 17-18 I would be pretty cool about it. My mom is the same. She told me earlier on that if I wanted to smoke in college, I could. I just had to make sure to keep it moderate and not get addicted. But if it's definitely a younger teen a sit down would be more advisable on why he/she can't smoke. But banning cigs and punishing your teen would be the worst thing to do. Just calmly handle the situation.