How to Keep a Dog From Throwing Up. If your dog throws up once, it might be just that he ate something that doesn't agree with him and his body is expelling it. However, if the dog continues to throw up and is unable to keep food down, you need to take him to the vet as soon as possible. In the meantime, there are some things you can do to try to control the vomiting.
Give the dog a tsp. or two of Pepto Bismol. If your dog refuses the liquid form, try a chewable tablet.
Put the dog on a bland diet. Boil some chicken breast without the skin. Cut it into small pieces and mix it with brown rice. Only give the dog a couple of Tbsp. at a time.
Keep her drinking. It is important that your dog drink plenty of water to prevent dehydration. If she is having trouble keeping water down, try giving her ice cubes or ice chips to suck on. To test for dehydration, pinch a small amount of the dog's skin and watch how it responds when you release it. If the skin is slow returning to normal position, she is starting to dehydrate and needs emergency care.
Collect a stool sample and a sample of the vomit to bring with you to the vet's office. Keep the samples in the refrigerator to keep them fresh.