Why Does My Pet Have Diarrhea?

Nobody likes diarrhea. Loose and liquid bowel movements, sometimes accompanied by cramps and sudden urges to go, are just no fun, for you or your pet. Diarrhea is a symptom of something gone awry, anything from a change in diet to serious infection or illness. An occasional mild bout lasting no more than a day isn’t too worrisome, but a severe or prolonged attack requires veterinary care, not least of all because of the accompanying dehydration.pet-lying-down

Causes of Diarrhea

There are many roads to diarrhea, here are some of the most common:

  • Changes in diet, perhaps triggering a food intolerance
  • Ingestion of spoiled, infected, or toxic substances
  • Ingestion of foreign bodies, such as toys
  • Viruses, bacteria, or parasites
  • Allergic reactions, medications
  • Liver or kidney disease
  • Tumors
  • Colitis or hemorrhagic gastroenteritis
  • Stress

Notice that some causes are acute, resulting from specific episodes, whereas others are chronic, caused by disease.


As mentioned, loose or liquid stool, often frequent in nature, is the main symptom of diarrhea. This may be accompanied by straining, flatulence, mucus or blood in the stool, and volume changes. You might also observe vomiting, fever, dehydration, lethargy, loss of appetite and weight loss. Internal bleeding may be indicated by black stool, and should prompt an immediate trip to the vet.


Unless the symptoms are severe or you also notice lethargy, vomiting, fever, straining, poor appetite or black stool, you can treat you pet at home for a day. Avoid feeding it, but leave out plenty of fresh water to stave off dehydration. Contact your vet to describe the symptoms and follow the vet’s advice. If the symptoms don’t recede by the second day, bring your pet in to your veterinarian’s office for a full examination.

Your vet will check for dehydration and any underlying illnesses. The vet will take a stool sample to check for internal parasites and blood, as well as take blood samples for analysis. Depending on  the severity and length of specific symptoms, you vet might have to examine the inside of your pet with X-rays, biopsies, endoscopy, cultures, and ultrasound. cat-having-ultrasoundBear in mind that certain dog breeds are disproportionately prone to diarrhea. German shepherds, for example, often suffer from an insufficiency of exocrine pancreatic substances. Younger animals might be more likely to encounter parasitic or infectious disorders than are their older brethren.

If tumors are found, surgery might be required. Kidney and liver diseases might require aggressive treatment, including stays in a pet hospital.

Preventing Diarrhea

An ounce of prevention can prevent a pound of loose stool. Here are a few helpful tips you can apply to save your pet from experiencing diarrhea:

  • Ensure your pet is properly vaccinated
  • Treat or prevent parasites as directed by your veterinarian
  • Keep your pet away from tainted food and garbage
  • Introduce new foods gradually
  • When walking your dog, be vigilant against it feeding on wild plants or dirty water
  • Never let your pet ingest the waste products of other animals. Prevent a dog’s access to a cat litter box.
  • Try to minimize stress in your pet’s life. If you live in the flight path of an airport, work with a trainer to desensitize the animal (or move to a quieter part of town). Ensure your pet gets enough exercise. If it suffers from separation anxiety, think about getting another pet to keep it company while you’re away. Dogs suffering from psychological problems can receive therapy and medications that might make a big difference.

Your veterinarian has the knowledge and experience to diagnose and treat your pet’s diarrhea, so always keep your vet informed when symptoms arise.