If you have a scratchy throat and cough use whisky, hot water, sugar (or honey) and lemon or whisky hot water and Lemsip(I import mine from the UK).
If you just want something to keep your throat in good order while singing use a good British hard cider, still if possible, I always found Triple Vintage worked well but here in the States have to make do with Blackthorn. Don't use the American stuff though! A shot of rum in the cider helps too!