what cab i do for my puppies upset stomach?

Adopted a 7 month old boxer puppy from the vet on Thursday. She was surrended 2 days before. Don't know what she was eating before, but put her on a good high protein puppy food. She has been throwing up some and her farts smell like sulphur. I cut back the food but want to know if there is anything I can do to help her feel better. Can't get to a vet til tomorrow. Her stools are fine.

First thing is first --- forget all this "High protein is best" nonsense I'm sure you've read about on the net. Most people online haven't got the foggiest idea about nutrition, and go simply based on random annecdotes, and what they read about online (which is written by similarly ill informed people). The actual protein *requirement* for dogs is quite low relative to some of these 'ultra high protein' diets you see on the market. The reason your pup has foul smelling gas, is because the protein is getting through to the large intestine, where it is being degraded by the normal flora (microorganisms). They produce nasty smelling gases that then make their way out the back end. My advice --- call the vet, and find out what they had been feeding. Feed that. Despite the popular mythology, many (most?) vets do in fact know quite a bit about nutrition, and you can probably trust their judgement on this one.