What is the most common cause of gastroenteritis in dogs?

Any dog owner knows that sinking feeling when your pup starts vomiting or having loose stools. Gastroenteritis, the inflammation of the stomach and intestines, is one of the most common issues vets see—and its root cause often ties back to what our dogs eat. More than half the cases we encounter trace to dietary indiscretion, a fancy term for when dogs get into foods they shouldn’t.

Dogs are curious creatures, and that curiosity can lead them to scarf down table scraps, expired kibble, or even garbage during walks. In many neighborhoods, where trash bins are left curbside for pickup, it’s easy for a curious pup to sneak a snack—something that might violate local pet containment rules, too. Foods like chocolate, onions, or grapes (all toxic to dogs) are common culprits, especially during family gatherings where plates get left within reach.

Another big trigger? Sudden changes to their regular diet. Switching kibble brands overnight or adding too many new treats can shock a dog’s sensitive digestive system. It’s not just about what’s in the food, but how consistent it is—vets always recommend gradual transitions, which aligns with best practices for responsible pet care in most regions.

While diet is top of the list, bacterial or viral infections can also cause gastroenteritis. Cases of parvovirus or salmonella pop up, especially in unvaccinated puppies or dogs that frequent dog parks. Staying on top of vaccine schedules isn’t just a good idea—it’s often required by local animal welfare laws to protect both your pet and the community.

Stress can worsen or even trigger gastroenteritis, too. Moving to a new home, a change in routine, or even a family member being away can throw a dog’s system off balance. It’s easy to overlook, but keeping a calm, consistent environment does more than just make your pup happy—it supports their digestive health, too.

If your dog shows signs like persistent vomiting, diarrhea with blood, or lethargy, don’t wait to call the vet. Catching gastroenteritis early can prevent dehydration and more serious issues. By sticking to a regular diet, keeping toxic foods out of reach, and following local pet care guidelines, you’ll lower the risk of this painful condition—and keep your furry friend healthy and active for years to come.