There are a few things that you can do if your dog is vomiting. One is to withhold food and water for a few hours to allow the stomach to empty. If your dog is drinking water, this will help to keep them hydrated. You can also give them ice chips or diluted chicken or beef broth. You can also give him activated charcoal, which can help absorb any toxins in the stomach. If your dog is not keeping anything down, you should take them to the veterinarian.