How to deal with my friend's vomiting?

My friend, Mel, who is 17, is currently at my house. I was smoking in front of her, as I am a chain-smoker and she doesn't mind second-hand smoke, and she said, ''Could I have a puff?'' I handed her my cigarette, and she took a puff, which she didn't inhale. I thought her how to properly inhale, and before I knew it, she was vomiting all over my new couch, for she has a very weak stomach and vomits about three times daily when she's upset or overly happy. Now, she is locked in the bathroom, vomiting, and I don't know who to turn to for help...