When a dog has an upset stomach, Canine Journal recommends feeding him rice and boneless boiled chicken with no salt. Banana baby food is also suggested. A dog may also seek out and eat grass as a natural remedy to make himself vomit.
Canine Journal states that Pepto-Bismol and crushed Pepcid are safe to feed a dog, provided that a veterinarian gives a recommendation on the amount. Always provide a dog access to clean, fresh water, especially if he has been eating grass. If he has had diarrhea or is vomiting continuously, he may need powdered animal-grade Pedialyte mixed into his water to help replenish lost electrolytes and minerals. Dehydration can progress quickly in a dog, and he may need medical help.
If a dog is resistant to eating with an upset stomach, Canine Journal recommends filling a needle-less syringe with Pedialyte and water, then injecting it down a dog's throat. If he refuses to swallow, hold his mouth, and massage his throat to stimulate the swallowing reflex.
The most common causes of upset stomachs in dogs are either house plants or a change in diet, according to Canine Journal. Plants such as aloe and holly can produce toxic reactions in dogs, according to the American Society for the Prevention of Cruelty to Animals. When changing a dog's diet, spend a week helping him transition by mixing the two foods together until he can safely tolerate it.