Both of the clubs I'm involved with are non-smoking. One of the reasons why Rosie Hardman stopped gigging was the smoke - she became allergic to it.

As far as your voice is concerned, you'll have to pace yourself carefully. I've learned how to 'back off' without noticeably losing volume, and it helps to keep the throat clear. Doing folk trains helped, as you can't battle against the noisy train an expect to have a voice left!!

I would suggest that nothing you pour down your throat during a gig is really going to help - all it may do is to make you think you are okay, so you work a bit harder, drink some more, then suddenly the voice goes... not good.