Gastroenteritis in Dogs: The Post-Thanksgiving Digestive Tract Blues

Patrick Mahaney, VMD, CVA, CVJ
Published: December 03, 2013
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Back in 2001, my first non-internship emergency shift was the weekend after Thanksgiving at the Metropolitan Emergency Animal Clinic (M.E.A.C.) in Rockville, MD. During my orientation, my boss informed me about the significant number of cases I’d be called upon to see involving some form of digestive tract upset, such as vomit, diarrhea, or decreased appetite.

Collectively, we’ll cluster the above clinical signs under the term gastroenteritis.

Technically, gastroenteritis is inflammation of the stomach and small intestines. Gastro- pertains to the stomach. Enter- relates to the intestines. -Itis means “inflammation of.” Put it all together and you have a not-so-well-feeling pet attached to an owner who is miffed about needing to clean an expensive carpet or car interior.

So, what clinical signs can be seen in gastroenteritis cases? Here’s the breakdown:

Gastritis and Vomit (Emesis)

Vomit (emesis) occurs upon active contraction of the stomach to bring up its contents. Vomit should be differentiated from regurgitation, which occurs when food, liquid, or other material emerges in a passive process that lacks abdominal contraction.

Gastritis is inflammation of the stomach’s inner lining, which then leads to vomit.

Any material that is consumed to which the body is not acclimated to, or which causes an inflammatory reaction, will cause the stomach to contract and promptly eject the material through the esophagus (food tube) and mouth. Substances having difficulty moving from the stomach into the small intestine also end up lingering in the stomach and ultimately may be vomited (or remain in the stomach and cause a foreign body obstruction).


When having the diarrhea discussion, we have to consider from what part of the intestines the issue emanates. As dogs and cats have large and small intestinal tracts, both small and large bowel diarrhea can occur.

Small bowel diarrhea stems from problems affecting the small intestine, which is the part of the digestive tract that connects the stomach to the large intestine (colon). Small bowel diarrhea often takes on a pale appearance, lacks urgency in its production, and has a mushy consistency.

Large bowel diarrhea (colitis) comes from the colon, appears vastly different from its small bowel counterpart, and has one or all the following characteristics:

  • Liquid consistency
  • Urgency or increased frequency
  • Large or small volume
  • Straining (tenesmus), which is often mistaken for constipation
  • Mucous
  • Blood
  • Flatulence (farting, passing gas, etc.)

Anorexia (decreased appetite)

Nearly any ailment of the stomach, intestines, esophagus, kidneys, liver, or other organ system can cause anorexia. Anorexia can be partial or complete. A pet having partial anorexia may still be interested in consuming certain foods. Conversely, completely anorexic pets refuse all foods.

Anorexia may be completely unrelated to the digestive tract or internal organs, as severe periodontal disease can cause pain while chewing or swallowing and dissuade a pet from normally eating.

So, why do pets have post-Thanksgiving gastroenteritis? Well, pet owners commonly share their festive foods with their canine and feline companions.

As you read in my previous Daily Vet post (Can You Feed Your Pet Thanksgiving Foods?), I’m an advocate of owners judiciously sharing festive foods with their canine and feline companions. Yet, some owners don’t go the judicious route. Additionally, the majority of pets in the U.S. are not acclimated to eating human foods. Plus, Thanksgiving foods are typically richer in protein or fat, so pets are more prone to gastroenteritis (and pancreatitis, but that’s an altogether different topic). 

Every day I witness the phenomena of my own personal pooch (Cardiff), and many of my patients who eat whole-food diets, being less prone to gastroenteritis from dietary changes. This year, Cardiff enjoyed a scrumptious meal of turkey breast, sweet potato, turnip, and sautéed greens for his Thanksgiving dinner and exhibited no subsequent digestive changes.

With any digestive tract ailment, it is important that your pet sees your veterinarian for a physical examination and any recommended diagnostic testing. The most common diagnostics performed on pets having gastroenteritis include:

  • Blood, fecal, and urine testing — These tests permit the determination of normal vs. abnormal levels, or the presence of infectious organisms that may be contributing to disease.
  • Radiographs (X-rays) — This imaging technique permits the visualization of gross changes in the bones, joints, and soft tissues. During episodes of gastroenteritis, the abdominal organs, including the stomach, small and large intestines, spleen, liver, and urinary bladder, are assessed.
  • Ultrasound — Imaging via ultrasound is a different technology which permits the determination of more subtle changes in abdominal tissues as compared to radiographs. Health concerns insufficiently clarified by radiographs usually are more accurately visualized with ultrasound.

The treatment of gastroenteritis often involves fluid therapy (intravenous or subcutaneous), medications (antibiotics, anti-parasitics, etc.), nutraceuticals (supplements like probiotics, natural anti-inflammatory herbs, etc.), dietary modification (bland, moist, whole food based diet, etc.), or others. Mild gastroenteritis may resolve with no or minimal treatment while severe episodes require significant medical intervention to resolve.

By the way, my boss was right. I saw a plethora of gastroenteritis cases over that weekend and in association with other holidays.

Pet owners can minimize the potential for gastroenteritis as the result of human food consumption by incorporating appropriate human foods into a pet’s diet on a regular basis. Additionally, having our canine and feline companions consume a whole-food based diet can reduce their intake of highly processed, commercially available dog or cat foods made of less-than-ideal ingredients (i.e., feed-grade), which are capable of causing both short and long term health consequences.

Pumpkin has many health benefits for our pets and is one of the human foods that owners can safely and regularly add to our pet’s diet.  Some of the nutritional benefits of pumpkin include:


Pumpkin contains nearly three grams of fiber per one cup serving. Fiber promotes a sense of fullness and can potentially enhance weight loss by reducing the physiological urge to consume larger volumes of food.

Additionally, fiber can help with feline constipation. As cats mature into their adult and geriatric years, constipation is a serious problem requiring a multi-faceted solution with the primary emphasis being placed on diet. Increasing fiber levels creates more stool bulk, thereby stimulating the colon wall and promoting contraction of the muscles responsible for moving stool from its origin in the ascending colon through the rectum (the three parts of the colon are the ascending, transverse, and descending colon, which then connects to the rectum).

Increased dietary fiber can also help pets suffering from diarrhea. Both cats and dogs are prone to large bowel diarrhea (also known as colitis), often from food changes or dietary indiscretion (eating something that one should not).

Diarrhea is characterized as either large or small bowel diarrhea depending on a number of characteristics. Large bowel diarrhea comes from the colon and is also known as colitis. The nature of large bowel diarrhea appears vastly different from its small bowel counterpart and may have one or all the following characteristics: mucus, blood, urgency to defecate, flatulence, and large or small volume bowel movements. Small bowel diarrhea relates to the small intestine, which is the part of the digestive tract that connects the stomach to the large intestine (colon). Small bowel diarrhea often takes on a pale appearance, lacks urgency in its production, and has a mushy consistency.  

Dr. Patrick Mahaney

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