Almost all dogs suffer from gastroenteritis at one time or another because they’re scavengers and will sample just about anything they're curious about. Dogs have a well-developed vomiting reflex that allows them to expel food or non-food items that are toxic or otherwise not appropriate. Thus gastroenteritis probably serves an evolutionary purpose, but the bad news is that it can be fatal to small breeds and puppies because it can cause extreme dehydration and electrolyte imbalance.

What are some of the culprits in gastroenteritis? The multitude of reasons dogs may develop gastroenteritis are food allergies, infections caused by pathogens (bacteria, viruses, funguses and parasites), dead animals, certain plants, poisons (antifreeze, herbicides, rodenticides, insecticides, bleach), whipworms, hookworms, prescription medications, physical obstruction or complete blockage of the gastrointestinal system (foreign bodies like bones or plastic, tumors, etc.), intussusception (a telescoping bowel that pinches off the bowel pathway), specific diseases (diabetes mellitus, kidney or liver disease, peritonitis, pancreatitis, sepsis, inflammatory bowel disease, and stomach ulcers) or even psychological stress.

How can you recognize gastroenteritis? Symptoms of gastroenteritis besides vomiting, watery diarrhea and dehydration include depression, lethargy, lack of appetite, a painful abdomen, borborygmi (grumbling noises in the stomach), and bloody vomit or diarrhea or bile in the vomit.

If there is bloody vomit or diarrhea, the condition is called hemorrhagic gastroenteritis, which generally attacks smaller and younger dogs and must be treated by a veterinarian. The cause of hemorrhagic gastroenteritis remains somewhat of a mystery. It may be an abnormal response to bacteria or a dietary issue. Stress and hyperactivity may contribute to this potentially serious disease.

Is it easy to treat? Yes and no. In most cases, gastroenteritis, once diagnosed through a history and physical and analysis of the vomit and diarrhea, disappears on its own. But in smaller dogs or puppies or any dog with persistent vomiting and diarrhea, dehydration, any other unexplained symptoms, or blood in the emesis or stool, further testing is needed. A CBC (complete blood count), fecal exam, tests for viral infections like parvovirus or coronavirus, urinalysis, and abdominal x-rays may be called for.

Treatment for garden variety gastroenteritis is to hydrate and give the GI tract a rest with IV fluids and electrolytes, medications to stop the symptoms and sooth the GI tract, and fasting for a day, then adding water and a bland diet for a few days. A new protein source other than the usual one should be given at first in case there is food sensitivity suspected. In the case of hemorrhagic gastroenteritis or if an infectious cause is suspected, antibiotics are administered.

Holistic veterinarian Dr. Shawn Messonnier recommends probiotics like Acidophilus to restore the proper intestinal flora, especially if the dog is receiving antibiotics. Another good choice is fructo-oligosaccharides (FOS), natural plant sugars that are broken down in the colon and stimulate healthy gut bacteria. Additional natural products that can be used to enhance but not replace conventional treatment are MSM, omega-3 fatty acids, glucosamine, aloe vera, calendula, chamomile, marshmallow, raspberry leaf and slippery elm.

How do you reduce the chances of gastroenteritis in your dog? Prevent your dog from Dumpster diving, use a short leash on walks to make sure he doesn’t pick up something on the street, keep him away from any dangerous objects that he could swallow, and make sure his vaccines for infectious diseases still protect him.

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