I have a pit bull mix who is approx 8yrs. Last evening he started having diahrea and today so far he has vomited 2 times and has had diahrea 3 times. We did give him a different kind of dog food last evening. We also live in Nevada were it has been very very hot the last 2 days.
Bailey won't eat or drink any water today. What can we do?

What did the vet tell you to do?

When you changed dog foods how did you do it? Did you switch slowly, or just start the new food abruptly? It's very hard on a dogs system to suddenly get new food. The way to switch foods correctly is to start with 1/4 new food 3/4 old for a few days, then 1/2 new 1/2 old for a few days, then 3/4 new 1/4 old for a few days, then all new. If the dog has any negative reaction during any of these stages you should wait longer to go to the next step or discontinue the new food.

Having said that, we can't tell you if your dog is having a reaction to the new food. This could be anything. Right now it's important to keep the dog hydrated. Buy some pedialyte or gatorade, feed to the dog, force feed if you have to. Do this until you can get into the vet, and that should be done asap.