When Your Pet Has Diarrhea


“Diarrhea is one of the most common medical symptoms of cats and dogs,” says Dr. Sheila McCullough, veterinarian at the University of Illinois College of Veterinary Medicine Teaching Hospital. “An owner’s first reaction to diarrhea should be to note when it started, how often it is happening, how much your pet is straining to defecate, and what the character of the diarrhea is – bloody, black, mucous-like, or otherwise. In addition, you should try to recall unusual items that your pet may have eaten.”

Diarrhea occurs when an accumulation of dissolved substances in the intestine causes excess water to move into the intestine. “This accumulation may be a result of decreased absorption of food, increased secretion of electrolytes by the intestine, or both. An example of overload of an absorbable solute is fructose overload. For instance, if you eat three pounds of grapes, an hour later you may be in trouble,” says Dr. Aslam Hassan, professor of gastrointestinal physiology at the college. Fructose needs help to be absorbed into the body. These helpers come in the form of carriers. If there is too much fructose, carriers may not be numerous enough to be effective. A lot of fructose will be retained in the bowel causing diarrhea. If your pet eats something it cannot absorb, i.e., adult cats and dogs can’t absorb milk sugar lactose, the overload of solutes in the intestine may cause diarrhea.

If not much intestine is functioning, there is a decreased amount of area to absorb food. This decreased surface area can be caused by surgical removal of a part of the bowel, diseased state of the bowel, or decreased interaction time between the intestine and food.  

Mucosa, the lining of the intestine, needs time to absorb what is ingested. Diseases can cause more rapid movement of food through the intestine.

Veterinarians may suggest motility modifiers (drugs that can increase or decrease movement of food through the intestines) to help control the diarrhea for 24 to 48 hours until diagnoses can be made. Motility modifiers should not be used long term. “For example, if your pet has E. coli-induced diarrhea, motility modifiers will retain the toxin that E. coli secretes and may cause life-threatening distention of the bowel,” explains Dr. Hassan.

It is important to realize that a high frequency of bowel movements is not synonymous with diarrhea. Your pet can have more than one bowel movement a day; as long as the amount of fecal water is normal, that’s OK.

When diarrhea begins in your pet, notify your veterinarian for help in deciding whether you should wait the diarrhea out or make an appointment to have the problem assessed. This is especially significant in young pets. “If your puppy or kitten who has not had its vaccination series gets diarrhea, you should call your veterinarian right away,” says Dr. McCullough.

“Viral diarrheas, such as parvo virus, could kill your young pet. Puppies and kittens dehydrate very quickly.” Veterinarians can initiate rehydration and fluid support.

For diarrhea in adult pets, Dr. McCullough suggests withholding food for 12 to 24 hours. “Then start your pet on small frequent meals of boiled hamburger and rice and see if the diarrhea stops.” However, if blood, foreign objects, or greasy feces are being passed, you should make an appointment with your veterinarian. Chronic diarrhea with sustained weight loss needs to be assessed by your veterinarian as well. “We need to find out whether weight loss is associated with diarrhea or something else,” explains Dr. McCullough.

Coming home to a pet unable to control bowel movements because of diarrhea is not a pleasant experience, as most pet owner’s know. When Dr. McCullough’s own animals have diarrhea, she puts them in a room with a linoleum floor that can easily be cleaned. Crating your dog with diarrhea may lead to a bigger mess. Not only will pets potentially cover themselves with their own feces, but pets may also direct the diarrheal spray outside of the cage and damage household items.

Dr. McCullough suggests these tips to prevent diarrhea in pets:

  • Don’t feed pets people food. People food may cause diarrhea as well as pancreatitis.
  • Keep pets away from foreign objects they can swallow.
  • Get puppies and kittens vaccinated and keep your pets away from unvaccinated animals.
  • Keep pets on a steady balanced diet; ask your veterinarian what the best diet is for your pet. Judys Health Cafe recommends Life’s Abundance Pet Food. If your pet requires a prescription food, consult your veterinarian.
  • Have your pet’s stool checked every year to control parasites.

Feces consistency and content are clues veterinarians rely on to tell them what might be occurring with your pet. You can use these clues as well if you watch your pet’s feces for changes. Also, when you do bring your pet to the veterinarian, bring a fresh stool sample.

For further information about diarrhea in pets, call your local veterinarian.

Article Courtesy of College of Veterinary Medicine Illinois