When your dog is sick with diarrhea and vomiting, it can be alarming — especially if they’re weak, not eating, or seem dehydrated.
These symptoms can appear suddenly or worsen over a few hours, leaving owners unsure what’s wrong or how serious it might be.
We outline the common causes of diarrhea and vomiting in dogs, what you can do at home, and when to seek veterinary help.
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Dog Sick Diarrhea and Vomiting — Why It Happens
Diarrhea and vomiting in dogs often occur when something irritates or inflames their stomach and intestines. This could be from eating spoiled food, a viral or bacterial infection, parasites, or underlying conditions like pancreatitis or liver disease.
Dogs may also vomit and have diarrhea due to dietary changes, stress, or ingesting toxins.
These symptoms are the body’s natural way of trying to eliminate harmful substances — but when they persist or are accompanied by lethargy and dehydration, veterinary care becomes crucial.
Dog Sick, Diarrhea and Vomiting: Common Causes
1. Dietary Indiscretion
Dogs are notorious scavengers. Eating garbage, spoiled food, or non-food items (like socks, grass, or table scraps) can easily upset their stomach.
When dogs ingest something foreign or toxic, their digestive system reacts with inflammation, leading to vomiting and diarrhea as it tries to expel the irritant. You may also notice signs like drooling, restlessness, or abdominal discomfort.
Most mild cases resolve within 24–48 hours, but if your dog continues vomiting, can’t keep water down, or becomes lethargic, they need to see a vet.
Read more: Dog Sick Diarrhea and Not Eating (Causes and treatment tips)
2. Sudden Diet Changes
Switching your dog’s food too quickly can wreak havoc on their digestive balance. Even a new treat brand or protein source can cause intestinal upset.
Diarrhea often starts within a day of the diet change and may be accompanied by gas, vomiting, and reduced appetite.
Always introduce new food gradually — mixing small amounts of the new food with the old over 7–10 days helps the gut adjust and prevents unnecessary distress.
3. Parasites
Intestinal worms (like roundworms, hookworms, or whipworms) and protozoa (like Giardia or Coccidia) can cause chronic diarrhea, vomiting, weight loss, and poor coat condition. Puppies and outdoor dogs are especially at risk.
These parasites damage the intestinal lining and interfere with nutrient absorption, leaving your dog weak and dehydrated. Routine deworming and fecal checks are the best prevention.
If your dog’s stool contains visible worms, blood, or mucus, or if they’re vomiting frequently, it’s time for a vet visit for diagnosis and proper treatment.
4. Infections (Viral or Bacterial)
Viruses like parvovirus, distemper, or coronavirus — and bacteria such as Salmonella or E. coli — can trigger severe vomiting and diarrhea.
These infections spread easily, especially in puppies or unvaccinated dogs, and can quickly lead to dehydration or shock. Symptoms often include fever, lethargy, foul-smelling stool, and loss of appetite.
Prompt veterinary care is essential because these infections can be life-threatening without treatment.
5. Pancreatitis
Pancreatitis occurs when the pancreas becomes inflamed, often after a fatty meal or table scraps.
A dog with pancreatitis may vomit repeatedly, have watery or greasy diarrhea, and show abdominal pain — sometimes sitting in a “praying position” to ease discomfort. The condition can vary from mild to severe and may recur if diet isn’t managed.
Pancreatitis requires strict dietary control, hydration support, and veterinary supervision.
6. Toxins and Poisoning
Household toxins — from cleaning products and medications to chocolate, xylitol, or plants like lilies — can cause vomiting, diarrhea, drooling, and tremors.
If you suspect your dog ingested something toxic, do not try to induce vomiting unless directed by your vet. Immediate veterinary care is critical, as many toxins can cause liver or kidney damage within hours.
7. Underlying Health Conditions
Chronic diseases such as liver disease, kidney failure, or inflammatory bowel disease (IBD) can also cause ongoing vomiting and diarrhea.
These conditions interfere with digestion and waste elimination, often leading to weight loss, dehydration, and general malaise.
Bloodwork and imaging help identify the root cause, and long-term management may involve prescription diets and medications.
Read more: Dog Sick Diarrhea (What it means and when to worry)
What to Do If Your Dog Is Sick, Has Diarrhea and Vomiting
If your dog has mild vomiting and diarrhea but is still alert, drinking water, and behaving normally, you can start with simple home care.
First, withhold food for 8–12 hours to let the stomach settle (but never withhold water). After that, offer small portions of bland food such as boiled chicken and white rice. Feed small meals several times a day until stools firm up.
Encourage hydration. Offer fresh water frequently or use an electrolyte solution approved for dogs. Dehydration can occur quickly, especially in puppies and small breeds.
Avoid giving over-the-counter medications without your vet’s advice — many human drugs are toxic to dogs.
If your dog improves within 24 hours, slowly reintroduce their regular food over the next few days. However, if vomiting or diarrhea persists or returns after eating, contact your vet.
It’s also wise to collect a stool sample for your vet to test if symptoms don’t resolve within 48 hours.
When to Call or Visit Your Vet
Contact your vet right away if your dog:
Vomits repeatedly or can’t keep water down
Has bloody or black, tarry diarrhea
Shows signs of dehydration (dry gums, sunken eyes, lethargy)
Is weak, shaking, or uninterested in food
Has a distended or painful belly
Is a puppy, senior dog, or has existing health issues
These symptoms may point to a serious condition like parvovirus, pancreatitis, or organ failure, which can worsen rapidly without prompt care.
If possible, bring a sample of vomit or stool to your vet — it can help with diagnosis.
Read more: Dog Sick Diarrhea Blood (Why it happens and what to do)
Key Takeaway
When your dog is sick with diarrhea and vomiting, it’s a sign their digestive system is struggling — and sometimes, it’s a clue to something more serious.
For mild cases, rest, hydration, and a bland diet can help your dog recover within a day or two. But if symptoms are severe, ongoing, or paired with weakness, blood, or dehydration, veterinary care is essential.
By acting early, you can prevent complications, restore your dog’s comfort, and protect their long-term health.