Causes of Vomiting in Dogs

by Lorie Huston, DVM  

There are many different diseases and disease processes that can cause vomiting in dogs.

Vomiting is only a symptom, not a disease in itself. 

If your dog is vomiting, especially if he is vomiting persistently or severely, finding the proper treatment relies on finding the cause of the vomiting.

Gastrointestinal Causes of Vomiting in Dogs

There are many diseases that affect that gastrointestinal (GI) tract that can cause your dog to vomit. These diseases range from mild and self-limiting in their nature to life-threatening. They may be accompanied by other symptoms such as diarrhea, lack of appetite, dehydration and more depending on the individual disease and severity of the illness.

Commonly encountered causes of GI vomiting include:

• dietary indiscretion (also sometimes known as “garbage can enteritis”)


• food intolerance/food allergies


• parasites (roundworms, hookworms, Giardia, coccidia, etc.)


• viral infections (canine parvovirus, coronavirus, canine distemper, etc.)


• bacterial infections (Salmonella, E. coli, etc.)


• foreign bodies


• intestinal obstruction


• intussusception (telescoping of the intestines which causes a functional obstruction)


• tumors/growths in the GI tract

Non-GI Causes of Canine Vomiting

While it is easy to always assume that vomiting is caused by gastrointestinal disease, this is not always the case. Systemic diseases can also cause vomiting, often as a result of toxins which build up in the blood stream.

There is a relatively long list of systemic diseases that can potentially cause vomiting. While there is not room here to list each and every one, these are some of the most common:

• kidney disease/kidney failure


• liver disease/liver failure


• pancreatitis (inflammation of the pancreas)


• pyometra (infection of the uterus)


• diabetes mellitus


• Addison’s disease (a disease of the adrenal gland)


• toxins/poisons

Diagnosing Vomiting in Dogs

In cases of mild vomiting, absolute diagnosis may not be necessary as the disease may be self-limiting. In these cases, fasting for a few hours followed by feeding a bland diet may be all that is necessary for recovery.

However, if vomiting is severe and frequent or accompanied by other serious symptoms, pursuing an accurate diagnosis will be necessary. If there is doubt about how serious your dog’s symptoms are, pursuing diagnosis immediately, rather than attempting the fasting/bland diet approach, may be advisable.

The basic diagnostic approach for vomiting is likely to include one or more of the following:

• fecal examination, checking for parasites and ova (eggs) of parasites


• a Giardia Elisa test on the feces


• a basic blood screen consisting of a complete blood count and blood chemistry profile, including blood electrolyte measurement


• abdominal radiographs (x-rays) and/or and abdominal ultrasound

Additional testing may or may not be necessary, depending on the results of these tests.

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Lorie Huston, DVM is an experienced veterinarian with over 20 years in practice caring for dogs and cats. 

She is an expert in pet health and pet care as well as being a talented free-lance author and blogger. 

In addition to numerous articles and posts both online and off, you can also find Lorie at her blog Pet Health Care Gazette. She is a co-host at the popular Animal Cafe and also works as a blogging/social media consultant and an SEO strategist. 

Her social media blog is Social Savvy Pets.

Articles by Dr. Huston:
Lyme Is Lame (Pun Intended)
The Ticking Bomb
Don’t Let Heartworm Become A Heartbreak!
Summer Perils: Blue-green Algae
Your Dog And Leptospirosis
Canine Parvovirus
Canine Distemper Virus
Why Is My Dog So Itchy? Top 5 Causes Of Itching In Dogs 
Vaccination Concerns and Potential Side Effects 
Natural Flea Control for Dogs 
Vomiting in Dogs: Is He Actually Vomiting? 

Related articles:
What’s In The Urine? (Part I)
What’s In The Urine? (Part II: Urinalysis)
Excessive Drinking
Bad Odor
Excessive Panting
Bad Breath (Halitosis)
Where There Is Smoke, There Is Fire: A Symptom Is Your Friend!
When Is It An Emergency?

Inflammatory Bowel Disease In Your Dog; Canine Chronic Diarrhea And Vomiting

What is Inflammatory Bowel Disease ?

Inflammatory bowel disease (IBD) is a catch-all term. It is used to describe many conditions with similar signs but different causes. It can be quite confusing to owners and veterinarians alike because IBD is also called, Chronic Colitis, Colitis, Irritable Bowel Syndrome, Lymphocytic-plasmacytic Inflammatory Bowel Disease, Regional Enteritis, Granulomatous Enteritis or Spastic Bowel Syndrome depending on what symptoms predominate. Basically, any time your dogs intestine remains irritated over long periods of time, some form of IBD is present. The signs of intestinal parasites can be similar to IBD. The classification is too complicated for anyone to agree on. This always happens when several poorly understood diseases cause similar signs. If you got to this page and you are uncertain if your pet has IBD, go here.

To further confuse matters, Irritable Bowel Syndrome in dogs, a stress-caused problem in dogs with similar signs to IBD , is often confused with IBD.

Occasional intestinal and stomach disorders are very common in dogs . Most cases are caused by eating things your pet shouldn’t – like spoiled foods, spicy treats, or trashcan waste. These usually cause a big mess and then correct themselves in a matter of days. But dogs with IBD have loose stools and diarrhea day after day.

In all forms of IBD, defense cells, accumulate in the walls of your pet’s digestive system. Sometimes this occurs because the pet is consuming things that do not agree with it or shouldn’t have been eaten. But just as frequently or more so, it is just that the pet’s body defenses have gotten out of whack and are mistakenly attacking compounds in the intestine that are really not a threat to the dog.

What Happens In Inflammatory Bowel Disease

When things irritate the lining of your pet’s intestine, they cause food to move through it faster. With time, this irritation causes the lining to thicken and become inflamed. Blood and tissue cells that normally fight bacteria and other invaders, accumulate within the lining of the inflamed intestines causing cramping, pain, colic, diarrhea and distress. These fragile intestines are more likely to bleed and they allow unhealthy intestinal organisms to proliferate and displace the healthy ones. These changes also make it harder for your pet to absorb nutrients from its food. When the beginning portions of the intestine are involved, the pet may also vomit or loose its appetite. When the final portions of the intestine are involved, the stool is loose, frequent, watery and sticky with mucus. Bright blood is often present when the lower intestine is involved (colitis).

These problems can be occasional or continuous. When they are continuous, pets often loose weight. It is also common for dogs with this condition to eat or chew on unusual items (pica) and it can be difficult to decide if pica is the cause or result of the problem.

Flatulence is also a common problem and so is a dull hair coat and heavy shed. When the lower intestine or colon is inflamed, the pet may strain and defecate more frequent, mucous-covered, stools.

Some types of IBD are genetic and are associated with certain breeds. The lymphocytic/plasmacytic form is one of these. It is most common in German Shepherd and Shar Pei dogs. Basenjis have their own form of the disease called immuno-proliferative IBD. Boxers suffer from a form called histiocytic ulcerative colitis while Irish setters have a wheat gluten-sensitive form of the disease.

The second most common form of IBD is Eosinophilic IBD. It tends to be more severe than the lymphocytic form, but it often gets better when diet changes are made. Eosinophils are blood cells involved in allergies – so food allergies are a suspected cause.

What Are The Signs Of Inflammatory Bowel Disease ?

The most common complaint is persistent loose stools, straining and diarrhea leading to accidents in the house. This occurs because the intestine is moving too fast and not given time to remove enough water from the things your dog ate. Irritation of the colon and anus causes the straining. We all know what that is like.

Dogs with this problem can also vomit. Some veterinarians include conditions that cause stomach irritation and vomiting in the IBD complex. I prefer to call those conditions gastritis . When vomiting occurs with IBD, it is due to inflammation in the upper small intestine just below the stomach. It is possible for a pet to have both conditions simultaneously.

Certain things hint as to what portion of the digestive tract is most inflamed. When vomiting and infrequent, bulky loose stools and weight loss predominate, we tend to think of a problem high in the intestine. When frequent smaller stools, straining, blood or mucus-flecked stools occur, we tend to think of a problem lower down in the intestines. Most often, a bit of both is occurring but one predominates.

Dogs with the high form may run low fevers. The may also have secondary bacterial intestinal infections. In general, pets with the high form of IBD look more ill.

WHAT CAUSES INFLAMMATORY BOWEL DISEASE ?

The most common form of IBD in dogs is the lymphocytic/plasmacytic form (LPIBD). This describes the type of cells that pathologists see when they examine biopsies from the pet’s intestine. Some of these cells are always there, but it is abnormal when they are found in large numbers. Since we rarely find anything present that should have drawn these cells to the area, we currently consider it similar to a false fire alarm. IBR is a common disease in humans, and physicians are just as stumped. When we find better treatments for pets, it will come through research designed to help humans with similar problems.

The second most common form of IBD is the form where pathologists see mainly eosinphils in unusually high numbers in the intestinal wall. These cases of Eosinophilic Inflammatory Bowel Disease are probably caused by food allergies. They can also be called food hypersensitivities. These are the cases where changing the protein sources in your pet’s diet helps most. Some dogs are not really allergic to food ingredients that bother them. It is their inability to digest or absorb certain nutrients (maldigestion-malabsorption) that leads to intestinal upset every time they are exposed to the ingredient(s). This is sometimes called mal-assimilation syndrome as well.

Chronic intestinal infections with bacteria, fungi or protozoa can also cause chronic diarrheas. Although pets get better when given the correct antibiotics, they often have an underlying intestinal problem that gave the organisms the opportunity to get out of control. However, salmonella and campylobacter infections can cause chronic IBD-like symptoms without underlying disease.

Granulomatous enteritis is another condition said to cause IBD in dogs. Granulomas are nodules of the body’s defense cells that accumulate around infectious organisms or foreign particles within the body. It is a specific disease in horses, but it may not represent any specific disease of dogs.

Dogs, especially older dogs, sometimes develop tumors of the intestines. When these tumors involve large segments of the intestine, they can cause symptoms similar to IBD.

To further confuse you, Irritable Bowel Syndrome (IBS) is not the same as Inflammatory Bowel disease (IBD). IBS has many of the same symptoms. But in IBS, the intestines are hyperactive, not from irritation, but from excessive nerve stimulation. The stimulation is usually psychological and due to stress, fear or nervousness. It occurs in dogs and is similar to what occurs in humans.
Click here to find out treatments, tests, other conditions and medications for IBD