The reasons dogs vomit are too numerous to provide a comprehensive list, and some reasons are unconcerning, while others are life-threatening. Our team at Stack Veterinary Hospital would like to educate you on why dogs vomit, and help you determine when they need an evaluation by a veterinary professional.

Is your dog vomiting or regurgitating?

Vomiting has three phases—nausea, retching, and forceful expulsion of gastric contents. In dogs, nausea is usually exhibited as nervousness and excessive drooling. Retching in dogs involves abdominal contractions, followed by expulsion of the gastric contents. By contrast, regurgitation is a passive act that involves expulsion of the esophageal contents. Vomit typically contains digested material, while regurgitation contains undigested matter.

Why is your dog vomiting?

Four principal areas—the gastrointestinal tract, vestibular region, chemoreceptor trigger zone, and cerebral cortex and thalamus—are responsible for activating your dog’s vomiting reflex.

  • Gastrointestinal reasons for your dog’s vomiting — Dogs most commonly vomit because of gastrointestinal tract problems. Some issues, such as dietary indiscretions, that result in vomiting are self-limiting and not concerning. Others are more problematic and include:
    • Infectious causes — Numerous viruses and bacteria can result in gastrointestinal upset, including vomiting. These conditions will be accompanied by other signs, such as fever and diarrhea. Several of these diseases are preventable by keeping your dog up to date on their vaccines.
    • Gastrointestinal blockage — Dogs who have ingested a foreign body that becomes lodged in their gastrointestinal tract will frequently vomit, or unsuccessfully attempt to vomit. Dogs experiencing gastric dilatation volvulus (GDV) may also exhibit similar signs. Other signs seen in dogs with these issues include pain, increased respiration, and abdominal distention. Typically, surgery is required to correct the blockage.
    • Gastric or intestinal inflammation — Inflammatory processes, such as gastric ulceration or pancreatitis, can result in vomiting. Dogs will also likely exhibit pain, and may vomit blood.
    • Ingesting a poisonous substance — If your dog ingests a poison, such as antifreeze or rodenticide, their gastrointestinal tract will become severely inflamed, resulting in vomiting. Several common household foods, including onions, grapes, and xylitol, are also poisonous to dogs. If you suspect your dog has ingested a poisonous substance, immediately contact Stack Veterinary Hospital or Animal Poison Control.
    • Parasites — A heavy parasite infestation can cause your dog to vomit. You may see worms in their vomit.
  • Vestibular reasons for your dog’s vomiting — The vestibular region is responsible for your dog’s balance and equilibrium, and includes the inner ear, vestibulocochlear nerve, the brain stem, and the vestibular cerebellum portion. Motion sickness occurs when the vestibular system is disturbed. Other vestibular issues that trigger vomiting include ear infections, stroke, cancer, and idiopathic vestibular disease. These dogs typically also exhibit signs such as a head tilt, leaning or falling to one side, circling, and odd eye movements.
    • Ear infections — Dogs who swim frequently, and those affected by allergies, are more prone to ear infections. Signs include odor and discharge from the ear, and head shaking.
    • Stroke — Older dogs are more susceptible to stroke, with rapid onset of vestibular signs.
    • Cancer — Cancers that invade the brain stem or vestibular cerebellum portion can cause vestibular signs.
    • Idiopathic vestibular disease with unknown cause — When no cause can be determined for vestibular signs, dogs are diagnosed with idiopathic vestibular disease. These cases typically start to improve in two to three days with no medical intervention.
  • Chemoreceptor trigger zone reasons for your dog’s vomiting — The chemoreceptor trigger zone (CTZ) is an area in the brain that receives input from drugs or hormones to initiate vomiting.
    • Drugs — Numerous drugs, such as chemotherapeutic drugs and heart medications, can cause vomiting in dogs.
    • Toxins in the blood — In dogs suffering from liver or kidney disease, toxins build up in their blood, causing irritation to the gastrointestinal mucosa, and frequently resulting in vomiting.
  • Cerebral cortex and thalamus reasons for your dog’s vomiting — Areas in your dog’s brain can be triggered during times of extreme stress or pain, resulting in vomiting.

When does your dog need veterinary attention?

If you are concerned about your dog’s vomiting, do not hesitate to call our team at Stack Veterinary Hospital for advice. Signs that indicate your dog requires veterinary attention include:

  • Continuous vomiting
  • Vomiting blood
  • Unsuccessful vomiting
  • Seizuring
  • Vomiting in conjunction with other signs, such as fever, lethargy, or diarrhea
  • Vomiting with weight loss
  • Suspected ingestion of a foreign body

How will your vomiting dog be diagnosed and treated?

Our American Animal Hospital Association (AAHA)-accredited Stack Veterinary Hospital team will ask you for a detailed history about your dog’s vomiting. We will run blood tests, and may perform X-rays or an ultrasound to determine the cause. Vomiting results in dehydration, electrolyte imbalance, and acid-base abnormalities. Our veterinary professionals may administer intravenous fluids to help correct these issues, and may prescribe anti-nausea medications to prevent further losses. Once we have determined the reason for your dog’s vomiting, our team will tailor a treatment plan based on the cause and your dog’s condition.

If your dog is vomiting, we always hope the issue is not cause for concern. However, if you suspect your dog does require veterinary attention, do not hesitate to contact our team at Stack Veterinary Hospital.