April 30, 2019

Cat Diarrhea

What causes diarrhea in cats?

Diarrhea is not a disease; rather, it is a symptom of many different diseases. Many mild cases of diarrhea can be resolved quickly with simple treatments. Others are the result of fatal illnesses, like cancer. Even diarrhea caused by mild illnesses may become fatal if treatment to prevent severe fluid and nutrient loss is not started soon enough.

We attempt to classify each case of diarrhea as either a major problem or a minor problem and localize the source of the diarrhea to the small intestine or large intestine (or both). It is important to determine how long the diarrhea has been present and whether the cat has lost weight. We use all this information to formulate a plan for diagnostic and therapeutic procedures.

Which cats are likely to get diarrhea?

Some potential risk factors for diarrhea include dietary indiscretion, exposure to cats with certain illnesses, a positive status for feline leukemia virus (FeLV) or feline immunodeficiency virus (FIV) and travel to areas of endemic fungal infection.)

What are the clinical signs of cat diarrhea?

With minor causes of diarrhea, the cat may have no signs of illness other than the loose stool. Major causes of diarrhea result in the cat being visibly ill and exhibiting several, but usually not all, of the following:

  • Vomiting
  • Dehydration
  • Loss of appetite
  • Abdominal pain
  • High fever
  • Lethargy
  • Bloody and/or watery diarrhea

What are the possible causes?

Minor causes of diarrhea include:

  • Stomach or intestinal viruses
  • Intestinal parasites
  • Dietary indiscretions (such as eating garbage or other offensive or irritating materials)

Major causes of diarrhea may include:

  • Inflammatory bowel disease
  • Neoplasia
  • Fungal or bacterial infection
  • Hyperthyroidism
  • Loss of pancreatic function

How is the cause of diarrhea diagnosed in cats?

If your cat does not exhibit the clinical signs of a major case of diarrhea, we classify the illness as a minor case. A minimum number of tests are performed to rule out common causes of minor diarrhea. These may include a physical examination, multiple fecal exams for parasites and X-rays.

For cats that are visibly ill with a major case of diarrhea, diagnostic procedures are usually implemented quickly. We perform a series of tests that allow us to make a diagnosis so specific treatment may be initiated as soon as possible. These may include tests for feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV), X-rays with or without barium, blood tests, stool cultures, biopsies of the intestinal tract, thyroid profiles and exploratory abdominal surgery. Once a specific diagnosis is made, treatment may include special medications, diets or surgery.

How is diarrhea treated in cats?

With minor cases of diarrhea, treatment may be geared toward one or more of the common causes of uncomplicated diarrhea. Even with negative fecal examinations, many cats with uncomplicated diarrhea are routinely treated for worms. Other therapies often include drugs to control the motility of or relieve inflammation in the intestinal tract and a restricted diet for a few days. This approach allows the body’s healing mechanisms to correct the problem.

With major causes of diarrhea, initial therapy may include fluid replacement, electrolyte replacement and antibiotics. Additional therapy will depend upon the diagnosis.

What is the prognosis for cats with diarrhea?

With minor cases of diarrhea, we expect improvement within two to four days of initiating therapy. If this does not occur, a change in medication or additional testing may be needed to further define possible causes. Please keep us informed of lack of expected improvement so that we may manage the situation properly.

Can diarrhea be transmitted from a cat to humans?

Some of the bacterial and parasitic causes of diarrhea are infectious to humans. If any members of your household are also experiencing diarrhea, it is important to let us know. This will allow the veterinarian and physician to work together in managing potentially infectious causes of the illness.


While caring for a new kitten or cat can certainly be one of the most fun and rewarding experiences you can have as a pet owner, if you are under-informed about the needs of your feline friend, you can leave them at a developmental or debilitating disadvantage.

At the Animal Clinic of Billings and Animal Surgery Clinic, cat care and kitten care is one of our greatest joys. Our veterinary staff would be delighted to spend some time with you and your feline companion ensuring that your relationship will be a healthy, happy and rewarding one for many years to come.

Please call to schedule a cat care or kitten care appointment with us today!