Be very careful to choose the right type of cough syrup when tussing. Choosing the wrong one can end you up in the emergency room or dead. The only listed active ingredient should be dextromethorphan hydrobromide. If you drink too much of the other types, say goodbye to mister liver. That said, it doesn't necessarily cause you to vomit -- it's just very common. That said, tussing is serious drug stuff...it's apparently a very heavy high, and not too fun for inexperienced users. Try something lighter for your first trip...