While it can be normal for dogs to vomit once or twice a year, vomiting on a more frequent basis is cause for concern. And, while it’s tempting to think that vomiting means the problem is in the stomach, know that vomiting is a truly nonspecific symptom. There are literally dozens of different diseases, many unrelated to the stomach, that can cause a dog to vomit. The most common causes of vomiting are listed below.

Eating something inappropriate
Dogs, particularly youngsters, are the kings and queens of eating things they shouldn’t. Whether it be raiding the garbage pail or getting into something nasty out in the yard, irritation of the stomach and intestines caused by eating such “yuck” can cause vomiting. Much like a case of food poisoning, this sort of vomiting typically resolves on its own after 12 to 24 hours.

Gastrointestinal foreign bodies
Bones, rocks, childrens’ toys, socks, underwear, corn cobs— you name it, and dogs have clogged up their bowels with it. Some foreign bodies ultimately pass through on their own, but others become lodged and cause persistent vomiting. Treatment requires removal of the foreign body, and this is best accomplished with surgery or a nonsurgical procedure called endoscopy.

Food allergies
Check out the label on a typical bag or can of dog food and you will find dozens of ingredients. Just as is the case for us, some dogs develop allergies to certain food products or additives. Most dogs with food allergies develop itchy skin, but for some dogs, vomiting is the main symptom. Elimination diets (those with fewer ingredients) often solve the vomiting problem for dogs with food allergies.

Inflammatory bowel disease
For reasons that aren’t altogether clear, some dogs develop inflammation within the lining of their bowel. Allergies may play a role. The most common symptoms of this disease are vomiting and diarrhea. Treatment typically involves diet modification and the use of antiinflammatory medications.

Toxicities
Vomiting can be caused by several different toxins that dogs may eat if they are given access. Examples are poisonous plants (including mushrooms), rotten meat or carcasses, human medications such as Tylenol® or ibuprofen, antifreeze, and snail bait. Treatment varies depending on the specific toxin ingested.

Pancreatitis
The pancreas is located directly adjacent to the stomach and upper small intestine. So, it makes sense that vomiting occurs when the pancreas becomes inflamed and irritiated. In addition to persistent vomiting, pancreatitis tends to cause lethargy and abdominal pain. Hospitalization is usually required for administration of medications and intravenous fluids. The cause of pancreatitis isn’t always clear, but in many cases it seemingly arises on the heels of eating something that is fat-laden, such as the skin off the Thanksgiving day turkey.

Liver disease
Vomiting is a common symptom associated with most every flavor of canine liver disease. Successful treatment of the liver disease (if possible) results in resolution of the vomiting.

Kidney failure
Kidney failure causes a number of symptoms, and one of the most common is vomiting. The mainstay of therapy for kidney failure is supplemental fluids. Additional treatments are dictated by the underlying cause of the kidney failure.

Learn about kidney disease here>

Gastrointestinal tumors
Tumors that arise within the stomach and/or intestines can be benign or malignant. Whatever the type of tumor, vomiting tends to be a common symptom, particularly if it is located in the stomach or upper small intestine. Treatment varies depending on the location and type of cancer present.

Pyometra
Pyometra literally means pus within the uterus. This disease occurs in unspayed female dogs, most commonly a few weeks following estrus (being in heat). Vomiting is a common symptom associated with pyometra. Treatment usually requires spaying with surgical removal of the uterus.

Addison’s Disease
The official name for this disease is “hypoadrenocorticism” which reflects a state of having too little cortisone. The adrenal glands are responsible for producing cortisone as well as aldosterone, a very important hormone that controls sodium and potassium levels within the bloodstream. Addison’s Disease occurs when the adrenal glands quit producing cortisone and/or aldosterone. Vomiting is one of several symptoms caused by this disease. Treatment of Addison’s Disease requires hormone replacement therapy and, depending on the severity of symptoms, a period of hospitalization may be required.

Eating grass
Do dogs vomit because they eat grass or do they eat grass because they feel the need to vomit? This is the classic “chicken versus egg” conundrum. Some dogs are simply grazers. They enjoy munching on greenery and do so without vomiting. On the other hand, consensus amongst veterinarians is that a feeling of nausea or intestinal discomfort induces many dogs to develop a yen for eating grass, leaves, twigs, dirt and whatever else Mother Nature is serving. While it’s tempting to blame the foliage for the vomiting, it is important to dig deeper to figure out why the dog felt the need to graze in the first place.

How the cause of vomiting is diagnosed
Before any diagnostic testing, a veterinarian begins by collecting a thorough history, including details about the vomiting such as frequency, time of day, material found in the vomit, anything unusual that might have been ingested, normal diet and all other symptoms observed.

Next comes a thorough physical examination. This may be followed by blood and urine testing (to evaluate liver, kidneys, pancreas, etc.) and/or imaging studies such as X-rays and ultrasound of the abdomen. In some cases, biopsies from the gastrointestinal tract are needed to confirm a diagnosis. Biopsies can be obtained surgically or via endoscopy.

If such testing is not feasible, empirical therapy (treatment without a clearcut diagnosis) such as changes in diet and/or medications will be an option. A tentative diagnosis is then made based on the dog’s response to therapy.

If your dog is vomiting more than a few times a year, scheduling a veterinary visit to figure out the cause is a really good idea. As with most medical issues, the sooner the problem is addressed, the better the outcome is likely to be.

Questions for your veterinarian

• What is the most likely causes of my dog’s vomiting?
• What diagnostic testing is warranted?
• What is the prognosis?
• Should my dog see a veterinarian who specializes in internal medicine?