When to See Your Veterinarian by Dr. Race Foster, DVM Drs. At one time or another every dog or cat has a bout of vomiting or diarrhea. Usually they've eaten something disagreeable, eaten too much, too fast or exercised too soon after eating, are overly excited or nervous, or their body is reacting to any of a number of other non-serious conditions. Take away all food and water so that the irritated intestinal tract can settle down.
Nothing makes a vomiting dog or cat vomit more than a big drink of water.
You may allow the pet to drink very small amounts, and in this short time, if your pet is otherwise healthy, you don't have to worry about dehydration. If the diarrhea resolves, after 24 hours, you may give your pet very small amounts of a bland food, such as drained, cooked hamburger mixed with an equal amount of cooked rice. Observe your pet closely. Think about and try to identify the cause of the problem. Watch how your pet vomits or eliminates so you can describe it to your vet if symptoms persist.