What causes dogs to have diarrhea and vomit?

There’s nothing worse than walking into the kitchen to find your pup hunched over, looking miserable, with a trail of mess to clean up. Diarrhea and vomiting in dogs are never fun, but they’re actually pretty common—often a sign that something’s off in their system. Before you panic, it helps to break down the possible causes, from minor hiccups to more serious issues.

One of the most frequent culprits is what vets call “dietary indiscretion”—fancy talk for your dog eating something they shouldn’t. Maybe they snuck a bite of your leftover pizza off the counter, raided the trash for expired chicken, or even nibbled on a houseplant. Bichons, with their curious noses, are especially prone to this. Their tummies are sensitive, so rich foods or sudden changes in diet can throw things off balance fast. Even switching their kibble too quickly without mixing old and new can trigger upset—always transition over 7-10 days to avoid this.

Infections and parasites are another big player. Viruses like parvovirus (common in unvaccinated puppies) or bacterial infections from contaminated water can cause severe vomiting and diarrhea. Worms, like roundworms or giardia, often sneak in through soil or other dogs’ feces, irritating the gut. If your dog spends time at dog parks or boarding facilities, these risks go up. Keep an eye out for other symptoms: lethargy, fever, or blood in their stool are red flags that need immediate vet attention.

Environmental factors can also stir things up. Stress—from moving to a new home, a new family member, or even a thunderstorm—can mess with a dog’s digestive system. Some pups get so anxious during fireworks season that they develop upset tummies. Medications, too, might have side effects; always check with your vet before giving them anything, even over-the-counter meds like ibuprofen (which is toxic to dogs).

It’s not just about your dog’s health—local laws often tie into responsible care. In many European countries, keeping your dog up-to-date on vaccinations (like parvovirus shots) is legally required, not just for their safety but for public health. If your dog has a contagious condition, letting them interact with other pets in public spaces could land you in hot water. Plus, cleaning up after a sick dog isn’t just polite—it prevents the spread of parasites or bacteria to other animals and humans. Always carry extra bags and disinfectant wipes when you’re out, especially if your pup isn’t feeling well.

Knowing when to call the vet is key. Occasional, short-lived episodes might resolve with rest and a bland diet (boiled chicken and rice works wonders). But if it lasts more than 24 hours, if your dog can’t keep water down, or if they’re acting weak, don’t wait. Dehydration sets in quickly, especially in small breeds, and early treatment can make all the difference. With a little detective work and quick action, you’ll have your pup back to their playful self in no time—minus the messy surprises.