There are many reasons Dog/Cat may have a disturbed stomach, however there's one normal cause: he ate something he shouldn't have. Vomiting and diarrhea are signs that a dog’s body is trying to expel something that shouldn’t be in their system. In a healthy dog, it’s a protective mechanism of the body that’s totally normal.
Stress may also trigger an upset stomach, as can bacteria imbalances in the gut and food sensitivities, which are most likely caused by dog’s diet. Diarrhea and vomit are the most obvious signs that dog’s stomach isn’t feeling right, but you should also keep an eye out for fatigue and loss lost of appetite. Your dog may gulp a lot to combat reflex, lick his lips, or even lick the air or objects, too. If he’s nauseous, you may also see him eat grass in order to soothe his stomach or try to induce vomiting.
An upset stomach once in a while is normal in dog, but when a dog suffers often, it could signal that something is wrong in his gastrointestinal tract.In that case look at your dog’s diet and staying away from foods that may create inflammation because of a food hypersensitivity, like chicken, lamb and venison. Instead, choose meats like beef, buffalo, and fish that shouldn’t irritate your dog’s GI tract. To maintain a healthy dog gut, you can also consider giving him a pre and probiotic.
When dog’s stomach is trying to get rid of something, it can be helpful to stop putting more things in his stomach for 12 to 24 hours. Fasting for that long is absolutely fine for the dog.