Gastroenteritis in Dogs

Gastroenteritis in Dogs

What is gastroenteritis?


Gastroenteritis is a medical term referring to inflammation of the gastrointestinal tract, usually the stomach and intestines. It can be caused by infection with bacteria, viruses, parasites, or reactions to medications or new foods. It often involves abdominal discomfort or pain, diarrhea and/or vomiting.

What are the signs of gastroenteritis?

"Most dogs with gastroenteritis will have intermittent episodes of vomiting and diarrhea."

Most dogs with gastroenteritis will have intermittent episodes of vomiting and diarrhea. The vomit may contain foamy, yellowish bile, especially after the stomach has been emptied. Many owners will observe "dry heaving" or "gagging" after their pet eats or drinks. Characteristically, there will be large volumes of diarrhea produced three to six times a day. The diarrhea may have a "soft ice cream" consistency and is often pale in color. Many dogs will be tender when picked up around the abdomen or will resist handling of the stomach and hindquarters. Most dogs affected with gastroenteritis will appear less active and have a decreased appetite. A low-grade fever is common. Dehydration can occur quickly if the vomiting and diarrhea persists for more than twenty-four hours.

How is gastroenteritis diagnosed?

Gastroenteritis is a diagnosis of exclusion. This means that your veterinarian will eliminate or rule out other more serious causes of the clinical signs before making a general diagnosis such as gastroenteritis. The first step toward determining what is causing a pet's vomiting, diarrhea, lethargy and other associated clinical signs are a good medical history.

Some key information in your dog's medical history includes:

  • Your dog's current diet, how much you feed and the frequency of feeding
  • Everything your dog ate or drank within the past forty-eight hours
  • Any new foods, treats or rewards
  • Any recent exposure to pesticides, medications, cleaning agents or any other new materials in your home environment
  • Any recent exposure to a new animal or person
  • Any previous episodes of vomiting and diarrhea (including their cause and treatment)
  • Any illness within the past month
  • Any chronic illnesses your dog may have
  • Any medications or supplements given within the past month

After obtaining the medical history, your veterinarian will perform a thorough physical examination. Your veterinarian will look for evidence of dehydration, abdominal pain or tenderness, bloating or gas, swellings, or any other physical abnormality. Your dog's temperature and other vital signs will be recorded.

At this stage, diagnostic testing will be recommended, and may include:

  • Complete blood cell count (CBC) - indicates the presence of dehydration and infection
  • Serum chemistries and electrolytes - detects organ system abnormalities and electrolyte imbalances due to vomiting and diarrhea
  • Urinalysis - detects urinary tract infections, kidney disease, dehydration, urine glucose for diabetes, etc.
  • Abdominal radiographs - to search for gastric (stomach) or intestinal obstruction or other abnormal findings
  • Abdominal ultrasound - to look for intestinal obstructions or other abnormalities

Your dog's specific diagnostic workup will be determined by the severity and duration of clinical signs, medical history and physical examination. Once the diagnostic tests are complete and other causes of the clinical signs have been eliminated, treatment will be prescribed.

What are some of the causes of gastroenteritis?

There are many causes of the symptoms of vomiting and diarrhea in dogs. Some of the more common conditions that your veterinarian will attempt to eliminate during the diagnostic workup include:

  • Systemic infections such as pneumonia, septicemia, urinary tract infection, meningitis
  • Foreign bodies or other obstructions
  • Intussusception (telescoping of the intestine upon itself)
  • Tumors
  • Poisoning or toxicosis
  • Exocrine pancreatic insufficiency
  • Hypoadrenocorticism (Addison's disease)
  • Thyroid disease

This is only a partial listing of some of the more serious conditions that can cause vomiting and diarrhea in dogs. Your veterinarian may discuss other possibilities based on your pet's specific condition.

How is gastroenteritis treated?

"The principal treatment of gastroenteritis is re-hydration..."

The principal treatment of gastroenteritis is re-hydration and restoration of blood electrolyte balance (sodium, potassium and/or chloride). Depending on the degree of dehydration, this fluid replacement will be given orally, subcutaneously (beneath the skin) or by intravenous (IV) treatment.

Antibiotics may be administered if the clinical signs are severe or if diagnostic tests suggest a bacterial infection. Antidiarrheal agents or drugs to alter intestinal motility (activity) may be used in certain conditions, after intestinal obstruction or other mechanical and anatomical issues have been ruled-out. If your pet is experiencing severe colitis, motility-modifying agents are generally not recommended.

Food (and sometimes water) is often withheld during the initial stages of treatment and then slowly reintroduced. Small, frequent feedings of a bland diet are generally prescribed. Your veterinarian will advise you on the best diet to feed your pet for a speedy recovery.

What is the prognosis for gastroenteritis?


Most cases of acute gastroenteritis improve rapidly after re-hydration. If the vomiting and diarrhea do not improve significantly within forty-eight hours of treatment, the diagnosis should be re-evaluated.

"Early recognition and treatment are the cornerstones to returning your dog to its normal healthy state as quickly as possible."

Gastroenteritis is a common condition seen in veterinary practice. Early recognition and treatment are the cornerstones to returning your dog to its normal healthy state as quickly as possible. If you have any further questions or concerns, feel free to contact your veterinarian. 

This client information sheet is based on material written by: Ernest Ward, DVM
© Copyright 2009 Lifelearn Inc. Used and/or modified with permission under license.