Pet Columns, Office of Public Engagement, College of Veterinary Medicine at the University of Illinois at Urbana-Champaign

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When Your Pet Has Diarrhea


Pet Column for the week of July 27, 1998


Office of Public Engagement
2001 S. Lincoln Ave.
Urbana, Illinois 61802
Phone: 217/333-2907
By Sarah Probst
Information Specialist

"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.
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.