Sick as a Dog (or Cat)

A vet breaks down when you should worry if your cat or dog is throwing up.

by Alycia Washington, DVM
June 15, 2021
grey and white cat with tongue sticking out
Vikafoto33 / Shutterstock

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Barf. Puke. Hurl. That there are so many synonyms for vomiting just goes to show you how common it is. But while you can typically pinpoint what caused you to do so (tequila shots, bad sushi, witnessing someone else throw up), diagnosing your pet isn’t so simple. Sometimes it was just a case of dog or cat nausea, and a bout of vomiting did the trick. No biggie. Other times, it’s the first sign of a serious issue. Knowing what health concerns could be to blame is a good start to figuring out why your dog or cat is vomiting.

Vomiting or Regurgitation?

The first step is to determine if your dog or cat is vomiting or regurgitating. Vomiting is active: the forceful expulsion of stomach contents, usually accompanied by retching and abdominal contractions. You know what this looks like. Regurgitation, on the other hand, is passive: stomach contents come out without warning. Picture a silence broken by a sudden, disgusting splat. These are two different symptoms with different underlying causes that either originate inside or outside the GI tract.

Alternately, if your dog is retching without producing any vomit — especially if accompanied by abdominal distension and pain — get them to the vet ASAP. It may be a sign of gastric dilatation and volvulus, a.k.a. ‘bloat,’ a serious diagnosis that requires emergency surgery.

Causes from Within the Gut

1. GI Obstruction

Gastrointestinal foreign bodies are a common cause of vomiting. When foreign material is ingested, it must make it past the stomach and through the intestines before coming out the other end. If it gets stuck at any point along the way, your cat or dog will vomit it back up. Dogs who regularly ingest toys, rocks, socks (the list goes on) are all at risk for developing obstructions. Cats aren’t innocent either. Yarn, shoelaces, and hair ties are common causes of obstructions in cats. Tumors in the GI tract can also block the passage of food and lead to similar signs. Puppy-proofing and kitty-proofing your home can help prevent these emergency situations.

2. Rotten or Toxic Food

Scavenging for rotten food out of the trash, eating toxic table scraps, or hunting rodents can all lead to inflammation of the GI tract, also known as gastroenteritis. Ingestion of toxic substances like household chemicals, medications, or plants can also cause cat or dog nausea.

Food Intolerance or Inflammatory Bowel Disease (IBD)

Pets with food intolerance or allergies can develop vomiting if the food contains ingredients that their gut can’t tolerate. This can lead to chronic inflammation in the GI tract. You may need to switch up your dog’s diet or cat’s diet to find something that they can tolerate.


Gastric ulcers from toxins, tumors, or kidney disease can also cause vomiting. If your dog or cat is vomiting blood (or vomit that contains dark specks of digested blood), that could be the first sign of an ulcer.


Cat hairball vomiting is very common and can be a result of normal self-grooming habits, especially in long-haired cats.

Infections or Infestations

Vomiting is a common symptom in puppies and kittens who have intestinal parasites or viral infections.

Causes from Outside the Gut


The pancreas is an organ located near the stomach that releases digestive enzymes. It can become inflamed after ingesting fatty foods, with diet change, or sometimes for no good reason. Here’s looking at you, Miniature Schnauzers (they are super susceptible). Pancreatitis can lead to vomiting, anorexia, and abdominal pain.

Organ Dysfunction

Kidney or liver disease can lead to nausea, poor appetite, and vomiting. Kidney disease can develop if your pet ingests something toxic (e.g. antifreeze, grapes, NSAIDs, or lilies), UTI, urinary obstruction, or chronic degeneration. Toxin ingestion, inflammation/cirrhosis, infection, and gall bladder obstruction are some common causes of liver disease.

Endocrine Disease

When endocrine diseases like diabetes mellitus or hyperthyroidism go undiagnosed or poorly regulated, vomiting can result due to the severe metabolic shifts involved.


Female cats and dogs that are not spayed can develop serious uterine infections (called pyometras) that can lead to vomiting, abdominal pain, and vaginal discharge.

Feeding Behavior

Certain behaviors like eating too much, too fast can cause meals to come back up as fast as they went down. If your pet tries to inhale an entire meal in one bite, there are tactics available to slow them down such as dog treat toys and cat puzzle feeders. Alternately, if they are a picky eater and go too long between meals, that can lead to your dog or cat vomiting bile.

What You Can Expect from Your Vet

As you can see, even this list of the most common reasons why pets can vomit is extensive, so it’s important for your veterinarian to gather as much information as possible to ensure that major health issues are caught as soon as possible. Be prepared to answer questions about your pet so they can get a better sense of the most likely cause of your dog or cat’s vomiting and recommend the most appropriate treatment.

  •  Does your pet still want to eat?

  • Can they hold down water?

  • How soon after eating or drinking does the vomiting occur?

  • What does the vomit look like?

  • Are they acting normally otherwise?

  • Does your pet like to eat or chew on inappropriate objects (even if you haven’t witnessed anything recently)?

You should be prepared to have some tests performed. X-rays are used to rule out intestinal obstruction and can sometimes reveal abdominal tumors. A blood test can screen for organ function issues or evidence of an infection. It can also reveal the secondary effects of vomiting and clue your vet into how aggressively your pet should be treated. Multiple episodes of vomiting can lead to severe dehydration that may require IV fluid therapy.

If your puppy is vomiting, your vet will probably start with a parvo test and fecal exam. If these initial tests don’t point to a clear cause, then an abdominal ultrasound may be the next step. And depending on the diagnosis, your vet could recommend outpatient care, oral or injectable medications, fluids, hospitalization, or even surgical intervention.

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alycia washington, dvm

Alycia Washington, DVM

Alycia Washington, DVM, is a small animal emergency veterinarian based in North Carolina. She works as a relief veterinarian and provides services to numerous emergency and specialty hospitals. Dr. Washington is also a children’s book author and freelance writer with a focus on veterinary medicine. She has a special fondness for turtles, honey bees, and penguins — none of which she treats. In her free time, Dr. Washington enjoys travel, good food, and good enough coffee.