Why Is My Dog’s Stomach Upset? 12 Possible Causes

An upset stomach, also known as gastroenteritis, is inflammation or irritation in the stomach or intestinal tract. It’s an umbrella term for digestive tract issues that can cause a range of symptoms in dogs. The most common are vomiting and diarrhea, which can be mild or severe, and appear suddenly or worsen over time.

Recognizing what's happening in your dog's digestive tract makes it easier to understand what’s going on.

“Mucus lines the inner walls of your dog’s stomach to protect it from acids while food is being digested,” says Dr. Boaz Man, owner and medical director of Boca Midtowne Animal Hospital in Boca Raton, Florida. “Bacterial, viral, and parasitic issues, foreign bodies, or systemic diseases can lead to gastritis, or inflammation of this stomach lining.” Similar problems can develop in your dog’s small and large intestine.

This is where your dog’s symptoms of vomiting and diarrhea usually begin.

Your dog’s symptoms can stem from a variety of causes.

Let’s look at 12 common reasons for an upset stomach in dogs.

1. Bacterial infections: Infection or overgrowth of bacteria in the gastrointestinal tract, leading to GI problems.
2. Certain human foods: Acidic, spicy, fatty foods, or food that is spoiled, such as when your pup gets into the garbage.
3. Chronic stress or anxiety: This can decrease appetite, lead to stomach ulcers or a damaged stomach lining, and cause vomiting.
4. Diet change: Sudden changes in diet can affect the gut microbiome and other aspects of the GI tract and cause diarrhea or vomiting.
5. Food allergies: Sensitivities to certain ingredients can cause stomach inflammation.
6. Foreign bodies: Ingested toys, clothing, or other objects may become lodged in the intestinal tract. This can become a surgical emergency.
7. Medical conditions: Liver and kidney disease, inflammatory bowel disease, pancreatitis, and some neurological diseases cause GI issues.
8. Medications: Antibiotics, steroids, non-steroidal anti-inflammatories, or other medications can irritate the stomach.
9. Motion sickness: Riding in the car can cause motion sickness and nausea in some dogs.
10. Parasites: Worms and microscopic organisms such as giardia cause GI problems.
11. Toxins: Certain plants, chemicals, and human foods may be toxic.
12. Viral infections: These include parvovirus, which causes severe stomach upset.

“Determining if it’s an emergency depends on how severe the symptoms are, how long they’ve gone on for, and the size and age of your dog,” Dr. Amy Attas, founder of City Pets, explains. Small dogs, puppies, and older dogs are susceptible to more serious problems.

Symptoms of an upset stomach in dogs can be quick to come and go, lasting only a day or two, which wouldn’t usually constitute an emergency visit unless they’re especially severe. But if symptoms persist, it can indicate the possibility of a more serious problem.

• Mild: Slightly decreased appetite is not an emergency. If your dog’s appetite doesn’t improve in a day or two, seek non-emergency care.
• Moderate: Decreased or no appetite with occasional diarrhea or vomiting can quickly become an emergency due to dehydration. Symptoms that continue for longer than 24 hours should also seek veterinary care.
• Severe: Nonstop vomiting or diarrhea and any evidence of blood in the stool requires emergency care.

When in doubt, it’s best to call your emergency vet hospital for guidance.

They may tell you that you can wait until your regular vet can see you or advise you to bring your dog to the hospital immediately for treatment.

If your dog has an upset stomach, your veterinarian will start with a complete physical exam and medical history.

They’ll likely perform diagnostic tests to determine the underlying cause of your dog’s symptoms. Blood work, fecal checks, and urine tests are often done.

Your vet may also suggest X-rays or an ultrasound of the abdomen to get a better look at your dog’s digestive system—especially if they suspect a foreign body.

“Be honest with your vet about any new food, treats, or table food your dog has ingested,” Dr. Man says. “It’s also important to let them know about any potential toxins your dog may have gotten into, including medications, house plants, cleaners, chemicals, drugs, or rat poison.”

Dr. Attas adds that pet parents should let their vet know if they frequently visit dog parks or doggy day care. Viruses, bacteria, and parasites can easily be passed from dog to dog in these locations, even if they’re fully vaccinated.

Treatment for upset stomach in dogs can range from oral medications to hospitalization and intensive care, depending upon the underlying cause.

Common treatments include:

• A bland or prescription diet
• IV or subcutaneous fluids for dehydration
• Antibiotics for a bacterial infection
• Antinausea medication, such as Cerenia®
• Antacids, such as omeprazole or famotidine
• Probiotics and fiber supplements
• Pain medication, which may be oral or injectable
• Plasma or blood transfusions
• Deworming or antiparasitic medications

For more extreme cases, surgery or hospitalization may be necessary.

“If your dog has a foreign object blocking their stomach or intestines, your vet will recommend surgery to remove it,” Dr. Man says.

If your dog has ingested a toxin, your vet may induce vomiting or administer activated charcoal to prevent it from being absorbed.

The best way to prevent an upset stomach in your dog is to stay aware of their diet and habits.

• No scavenging: If your pup is a notorious scavenger, keep the garbage locked away, or find one with a lid that your dog can’t get into. Same goes for litter boxes—keep your pup from eating any cat feces or compacted litter.
• Vaccinations: Keep your dog up to date on their vaccines, including parvovirus, which can affect a dog's GI tract. This is especially important in puppies.
• Check toys and chews: Monitor toys while your dog chews on them so they don’t ingest foreign materials. If a bone is getting small, or you notice cracks or chunks missing on toys, toss them.
• Diet changes: Feed your dog high-quality food that's appropriate for their age and life stage. “Don't make sudden changes to their diet, and if you do need to change it, introduce new food gradually over four weeks,” Dr. Man suggests.
• No toxins: Keep anything unsafe behind closed doors, or up and away from your dog’s curious nose.
• Drop it: It is beneficial to teach your dog a ‘leave it’ or ‘drop it’ command if they do come upon something potentially dangerous. Whether it’s medication on the floor or something outside during a walk, it can prevent future issues if they know when to leave something alone!

Q:What helps a dog’s upset stomach?

A:Feeding your dog a bland diet or adding probiotics to their food can help settle an upset stomach. However, it’s best to contact your vet for guidance on what to do, depending on what’s causing it. Some cases require veterinary treatment, such as bacterial infections or ingesting toxins.

Q:How long does an upset stomach last in a dog?

A:This will depend on what’s causing it. Symptoms may be fleeting, lasting only a day or two, but if they persist longer than that, it’s imperative to get them to a vet. Vomiting and diarrhea can lead to severe dehydration, which can be fatal if not treated quickly.

Q:What human medicine can I give my dog for an upset stomach?

A:Over-the-counter meds like omeprazole or famotidine may help your dog’s upset stomach (depending on what the underlying problem is), but only do so under your vet’s guidance.

Many human medicines can be toxic to dogs, so never give them something that your vet didn’t prescribe.