Acute Diarrhea (Loose Stools) in Dogs


Offending toxins include insecticides, lawn and garden products, and heavy metals.

  • Dietary intolerance may result in acute diarrhea when the animal is exposed to something in the diet that the intestines react to, such as certain proteins, lactose, high fat content, and certain food additives.
  • Many metabolic diseases (kidney and liver diseases) produce clinical signs of gastrointestinal disease, including diarrhea. Diarrhea may be bloody and is often accompanied by multiple systemic signs in these cases.
  • Pancreatitis, an inflammation of the pancreas, may also cause diarrhea.
  • Obstructions of the intestines usually present with vomiting, but acute diarrhea may also be noted.
  • Hemorrhagic gastroenteritis is a disease of uncertain origin in dogs. Affected dogs often have a sudden onset of bloody diarrhea.
  • Intussusception, which is the telescoping of the bowel on itself, may arise with bouts of acute diarrhea, and be present when the dog is examined.
  • Tumors of the intestinal tract or other abdominal organs may induce diarrhea. Although the diarrhea may begin acutely, it does not usually resolve on its own.

    Diagnosis In-depth

    Although most cases of acute diarrhea are short-lived and self-limiting, there are some cases that require diagnostic testing to confirm an underlying cause. Such tests include:

    • A complete history and physical examination
    • Fecal studies (flotation, smear, and zinc sulfate for Giardia) to test for intestinal parasitism. It is not uncommon to run multiple fecal exams, as some parasites are difficult to diagnose.
    • A complete blood count (CBC) to evaluate for infection, inflammation, anemia and dehydration.
    • A biochemical profile to help evaluate kidney and [[AWT3385|liver function, and electrolyte status]].
    • A urinalysis to evaluate kidney function and the hydration status of the animal.
    • Abdominal radiographs (x-rays) to evaluate the abdominal organs, and to check for the presence of fluid, gas or foreign bodies within the intestines.

      Depending upon the clinical signs and results of the above tests, your veterinarian may recommend additional tests to ensure optimal medical care. These ancillary tests are selected on a case-by-case basis:

    • Parvovirus test on the feces
    • Bacterial cultures of the feces
    • Fecal cytology to identify the type of inflammation present and to search for parasites, protozoa and bacteria
    • Serologic tests for infectious diseases
    • Laboratory tests for pancreatitis
    • Abdominal ultrasonography, especially if the previous diagnostics tests have been inconclusive
    • An upper gastrointestinal (GI) barium series to search for intestinal ulcers, masses, obstructions, intussusceptions and foreign bodies
    • Endoscopy or colonoscopy to evaluate a portion of the small intestine or colon with a viewing scope, especially if acute diarrhea progresses to chronic diarrhea
    • Specialized assays for toxins that can cause diarrhea

    Treatment In-depth

    Diarrhea is a symptom that can be caused by many different diseases or conditions, and specific treatment requires a diagnosis. Symptomatic therapy may be tried in mild cases of short duration, or may be instituted while diagnostic testing is underway. These treatments may reduce the severity of signs and offer relief to your pet:

    • Withholding food and placing the intestinal tract in a state of physiologic rest is an important aspect of therapy for acute diarrhea. Completely restricting food intake for 12- 24 hours allows the intestinal tract lining to start to heal.
    • Food is then gradually reintroduced, starting with a bland, easily digestible, low-fat diet. Initially small amounts of this food are given as frequent meals. Examples of such a bland diet include boiled chicken or beef, mixed with low-fat cottage cheese, boiled rice or potato. Prescription diets that may be administered for acute diarrhea include Hill’s Canine i/d, w/d, or d/d, Eukanuba Low Residue, and others. The bland diet is fed for several days, and then the original diet may be gradually reintroduced over a 2- to 3-day period.
    • Fluid therapy may be necessary in some patients with acute diarrhea to correct dehydration and acid-base derangements, to replace electrolytes that are deficient, and to provide for ongoing losses.
    • Antibiotic therapy for acute diarrhea is not required in most cases; however, it may be of benefit in animals that have hemorrhagic gastroenteritis, diarrhea containing fresh blood, or if a bacterial infection is suspected.
    • Empirical deworming is often recommended even if the stool sample is negative for intestinal parasites, because parasites do not always show up in the fecal examination.
    • Intestinal protectants and adsorbents (medications that coat, soothe and protect the lining of the intestines) may also be helpful.
    • If your dog does not respond to conventional therapy within 48 hours, if fresh blood is seen in the diarrhea, if the animal is vomiting or showing other signs of systemic illness, then a veterinary examination is warranted.

    Follow-up Care for Diarrhea in Dogs

    The best treatment for your dog requires a combination of home and professional veterinary care. For optimal follow-up success in the treatment of your pet, please do the following:

    • Precisely administer prescribed medications and follow any dietary recommendations. Contact your veterinarian if you are having difficulty treating your dog.
    • Watch your dog for worsening of the disease. Signs of worsening may include the onset of bloody diarrhea, persistence of signs for more than two days, or any signs to suggest a systemic illness (vomiting, weakness, anorexia, collapse).
    • If the signs resolve in a couple of days, no additional veterinary evaluation may be necessary.
    • Once the diarrhea has resolved, keep your dog on a consistent, balanced diet and restrict access to garbage and other things that can cause diarrhea.
    • Have your dog’s stool checked at least yearly for intestinal parasites. Consider year round administration of heartworm preventative drugs that also prevent intestinal parasites.
    • The prognosis for cure of self-limiting diarrhea is excellent. Affected animals are often successfully managed with dietary restriction, replacement of fluid deficits, and correction of the underlying cause.
    • If your dog’s diarrhea has failed to respond to the management outlined, it may require more extensive diagnostics. You should have your dog reevaluated by your veterinarian.


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