The most common cause of indigestion in dogs is dietary indiscretion, which simply means your dog ate something it shouldn’t have. But when stomach upset keeps coming back or doesn’t clear up within a day or two, the list of possible causes expands to include chronic inflammatory conditions, medication side effects, parasites, stress, and even problems with how the stomach empties itself.
Dietary Indiscretion: The Leading Cause
Veterinarians at the University of Illinois College of Veterinary Medicine identify dietary indiscretion as the single most common trigger of gastrointestinal upset across all ages of dogs. This covers a wide range of mischief: getting into the garbage, swallowing foreign objects, eating table scraps, or snacking on things like rabbit droppings during a walk. Even a sudden switch from one brand of dog food to another can throw off digestion, because a dog’s gut bacteria need time to adjust to new ingredients.
Eating too fast is another frequent culprit. Dogs that gulp their food swallow air along with it, leading to bloating, gas, and discomfort. Large or deep-chested breeds are especially prone to this, though it can happen with any dog.
Medications That Irritate the Gut
If your dog takes pain relievers for arthritis or joint problems, those drugs may be a hidden source of stomach trouble. Nonsteroidal anti-inflammatory drugs (NSAIDs) are the most common medication linked to stomach ulcers and erosions in dogs. In one study published in the Journal of Veterinary Internal Medicine, 83% of dogs on long-term NSAID therapy had erosions in their gastrointestinal tract, compared to a much lower rate in dogs not taking those drugs. The erosions appeared with every NSAID tested, including the most commonly prescribed options. Dogs had been on the medications for a median of six months.
Antibiotics can also cause nausea, vomiting, or loose stools by disrupting the balance of beneficial bacteria in the gut. If your dog’s stomach problems started around the same time as a new medication, that connection is worth raising with your vet.
Chronic Conditions Behind Recurring Symptoms
When indigestion isn’t a one-off event but keeps recurring over weeks or months, a deeper problem is often at play. The most common chronic causes include:
- Food-responsive enteropathy: A condition where the lining of the intestines stays chronically inflamed, often due to a sensitivity or intolerance to specific proteins in the diet. Symptoms include vomiting, diarrhea, gurgling stomach sounds, poor appetite, and weight loss.
- Gastritis and duodenitis: Inflammation of the stomach or the first section of the small intestine. In one veterinary study examining dogs with chronic digestive discomfort, 83% had visible signs of stomach inflammation and 66% had inflammation in the upper intestine during endoscopy.
- Acid reflux (GERD): When stomach contents move backward into the esophagus, dogs may gag, retch, lick their lips repeatedly, or appear nauseated without actually vomiting.
- Delayed stomach emptying: Some dogs have sluggish stomach motility, meaning food sits in the stomach longer than it should. This creates a feeling of fullness, discomfort, and nausea. Up to a third of humans with chronic digestive discomfort have delayed emptying, and the same pattern appears in dogs.
- Pancreatitis: Inflammation of the pancreas, often triggered by high-fat foods, causes intense abdominal pain, vomiting, and loss of appetite. It can range from mild to life-threatening.
These conditions overlap significantly in their symptoms, which makes pinpointing the exact cause without veterinary testing difficult. A dog with chronic vomiting could have a food sensitivity, a motility problem, or both at the same time.
Other Common Triggers
Parasites like roundworms, hookworms, and Giardia are a frequent cause of digestive upset, particularly in puppies and dogs that spend time in dog parks or kennels. Stress also plays a real role. Boarding, travel, a new family member, or changes in routine can trigger vomiting and diarrhea even in otherwise healthy dogs. Metabolic diseases, including problems with the adrenal glands, can mimic straightforward indigestion but require very different treatment.
How Vets Find the Root Cause
For a single mild episode, most vets won’t run tests. But when symptoms are severe, recurring, or accompanied by weight loss, the diagnostic process typically starts with bloodwork, a urine sample, and a fecal test to check for parasites. If those come back normal, your vet may order more targeted blood tests to evaluate pancreatic function, rule out adrenal gland disorders, or check whether your dog is absorbing nutrients properly.
Abdominal ultrasound is often the next step and tends to be more useful than endoscopy early on, because it shows whether the problem involves the small intestine, the large intestine, or whether there’s a mass that needs surgical attention. Endoscopy, where a camera is passed into the stomach and intestine, is typically reserved for dogs that don’t improve with initial treatment or whose symptoms are getting worse. When biopsies are taken during endoscopy, vets aim for 12 to 15 tissue samples from the small intestine to get an accurate picture.
Managing Mild Indigestion at Home
For a straightforward case where your dog vomited once or has mild diarrhea but is otherwise acting normal, a temporary bland diet is the standard approach. The classic recipe is boiled chicken breast mixed with plain cooked white rice. Feed smaller portions than usual, spread across four or more meals throughout the day instead of the typical two. This gives the digestive tract less work to do at any one time.
Most mild episodes resolve within 24 to 48 hours on a bland diet. Once stools return to normal, you can gradually reintroduce your dog’s regular food over three to five days by mixing increasing amounts into the bland diet.
Prevention comes down to consistency. Keep your dog on a stable diet of quality dog food, limit treats, avoid giving table scraps, and make sure garbage cans and countertops aren’t accessible. If your dog eats too fast, a slow-feeder bowl can help reduce air swallowing and the bloating that comes with it.
Signs That Need Immediate Attention
Simple indigestion and gastric dilatation-volvulus (GDV, commonly called bloat) can look similar in the early stages, but GDV is a life-threatening emergency. During GDV, the stomach fills with gas and twists on itself, cutting off blood flow. The expanding stomach compresses the chest cavity and restricts breathing. The stomach can rotate anywhere from 90 to 360 degrees, trapping the intestine and esophagus.
Signs that point to GDV rather than simple indigestion include a visibly swollen or tight abdomen, unproductive retching (trying to vomit but nothing comes up), restlessness or pacing, rapid breathing, and collapse. Large, deep-chested breeds like Great Danes, German Shepherds, and Standard Poodles are at highest risk. If your dog shows any combination of these symptoms, it needs emergency veterinary care within minutes, not hours.