If your pet is battling diarrhea, you’ll know it. Pets with diarrhea may defecate more frequently than usual, have accidents in the house, and may pass blood, mucus, or even parasites in their feces, which will be softer, looser or more watery than usual.

Most cases of diarrhea resolve in a matter or hours or days without intervention, but if your pet is suffering from loose stools for more than a couple of days, or if he also experiences vomiting, loss of appetite, or lethargy, you should take him to your veterinarian immediately. Small dogs, puppies and kittens with diarrhea are especially susceptible to dehydration, therefore they should be seen by their veterinarian more quickly.

In addition to loose or watery stools, pets with diarrhea may show signs such as:

  • Mucus or blood in the stools
  • Worms in the stools
  • Accidents in the house
  • Defecating with increased frequency
  • Straining to defecate
As we mentioned above, there are other signs that may indicate a more serious problem. It is worth recapping them here and adding a few to the list:

  • Nausea or vomiting
  • Fever
  • Loss of appetite
  • Lethargy (tiredness) or weakness
  • Abdominal pain
  • Weight loss


There are many reasons your pet may develop diarrhea. Most commonly, it occurs when he eats something that isn’t part of his normal diet (such as garbage) or when his diet changes abruptly. When switching from one kind of pet food to another, it’s best to make a slow transition over a week, gradually mixing in more of the new food and less of the old food, to allow your pet’s digestive system to adjust, decreasing the likelihood of diarrhea.

Other possible culprits include:

  • Bacterial overgrowth in the digestive tract
  • Viruses
  • Parasites
  • Ingestion of foreign objects, such as toys, bones, and fabric
  • Food allergies
  • Inflammatory bowel disease
  • Antibiotics and other drugs
  • Toxins
  • Pancreatitis
  • Diseases in other organs (such as liver disease)
  • Cancer

What To Do At Home

Here are some steps that you can take at home to help your pet start feeling better:

1. Assess your pet. If he seems to be feeling well and isn’t dealing with other symptoms, such as lethargy, poor appetite, or vomiting, and if the diarrhea is an isolated incident, meaning it resolves itself over a period of less than a few hours, you’re likely not dealing with an emergency situation. 

2. If your pet’s diarrhea is prolonged, unrelenting, or if it’s accompanied by a significant change in demeanor or the sudden onset of other significant symptoms, you should consider this an emergency. If your pet’s stool has bright red blood or you notice very dark or black stools, consider it an emergency. Call ahead and let your veterinary hospital or local ER know you’re on your way.

3. Keep track of the frequency and type of diarrhea (what it looks like), so you can talk to your veterinarian at your next regular visit. If you notice any increase in frequency or worsening of symptoms, however, make an appointment to see your veterinarian to have the condition checked out soon.

4. Feeding a bland diet, skipping a meal (for dogs only), or offering a veterinarian-recommended probiotic preparation might also help — but only for a short time. Call and seek your veterinarian’s advice if the symptoms persist and always before beginning any drug therapy.

What Your Veterinarian Will Do

Your pet’s doctor will follow several basic steps to figure out what’s causing your pet’s loose stools. These may include:

1. History: Your veterinarian will want to know the answers to questions such as: When did you first notice the problem? How has it changed? How has your pet been otherwise?

2. Physical examination: What a pet looks and feels like can tell veterinarians a whole lot about diarrhea. Checking out the entire pet is considered an essential step, even when investigating a seemingly simple case of garbage-eating.

3. Labwork: Your veterinarian may run any of the following basic tests: A CBC (complete blood count), blood chemistry, thyroid hormone test, urinalysis, and fecal examination. For cats, FIV (feline AIDS) and FeLV (feline leukemia) tests may also be recommended.

4. X-rays (radiography): This common imaging study will help examine the intestines and other abdominal organs. Most pets with diarrhea will be specifically evaluated for the presence of gas or abnormal objects in the stomach or intestines, the presence of masses, fluid in the abdominal cavity, and the abnormal size or appearance of organs (like an enlarged liver, for example).

5. Ultrasound: This test uses sound waves to help get a more three-dimensional sense of how things are working in the gastrointestinal system.

6. Gastrointestinal function tests: There are a variety of additional tests that can be conducted to determine the origin of the diarrhea symptoms. In cases of severe or recalcitrant diarrhea, or in cases in which the cause remains elusive, these tests can help accurately pinpoint the cause.

7. Endoscopy/colonoscopy and biopsy (to retrieve a tissue sample): This test is most commonly administered in cases of chronic diarrhea. Anesthesia is required.


Definitive treatment of diarrhea depends on the underlying cause. In mild cases, your veterinarian may recommend a bland diet that will be easy for your pet’s body to digest. If your veterinarian finds bacterial overgrowth, your pet may need probiotics or oral antibiotics to restore the normal balance of bacteria in the digestive tract. Medications to firm the stool or treat parasites may be necessary. Diarrhea caused by ingestion of foreign objects may require surgery.

More chronic cases of diarrhea are often treated with special diets and medications. In some cases, the underlying problem may not be completely cured and may need to be managed throughout the pet’s life. Your veterinarian can guide you to the best treatment for your pet.

This has been reviewed by a Veterinarian.