Diarrhea in Cats

By Ryan Llera, BSc, DVM; Krista Williams, BSc, DVM; Ernest Ward, DVM

Kitten is watching its owner clean its mess on the floorWhat is diarrhea?

Diarrhea is unformed or loose stools, usually with increased amount and frequency. It is a result of faster movement of fecal material through the intestine combined with decreased absorption of water, nutrients, and electrolytes. Diarrhea is not a disease, but rather is a sign of many different diseases. Diarrhea may occur as the only sign or as one of several signs of a more generalized problem, or with signs that result from prolonged or severe diarrhea.

How can I tell if my cat has diarrhea?

If your normally well-trained cat suddenly starts having accidents around the house and the stools are unformed to fluid, then diarrhea is obvious. However, if the cat is still using the litter box and covering up its feces or defecates outdoors, you may not initially notice diarrhea. Staining and soiling of the fur around the back end in longhaired breeds are often associated with diarrhea. It is important to remember that some variation in the consistency of stools occurs in healthy cats. If frequent liquid or semi-liquid stools persist for more than two days, you should consult your veterinarian. If you have more than one cat, you will need to determine which one has diarrhea or if it is occurring in multiple cats.

"If you have more than one cat, you will need to determine which one has diarrhea or if it is occurring in multiple cats."

What are some causes of diarrhea?

Infectious agents, such as bacteria, viruses, coccidia, and intestinal worms (hookworms, roundworms, whipworms), or non-infectious irritants, such as chemical toxins or poisonous plants, are some of the more common causes of diarrhea. Changes in diet, food intolerances, or allergies to specific ingredients in a diet can also be responsible for diarrhea.

How serious is diarrhea in cats?

The seriousness of diarrhea depends on how long the diarrhea has persisted and how many other clinical signs your cat has. If your cat has severe, bloody diarrhea and/or is showing more generalized signs of illness such as weakness, fever, vomiting, abdominal pain, dehydration, or loss of appetite, the problem may be very serious and medical attention should be sought as soon as possible.

How is the cause of diarrhea diagnosed?


Your veterinarian will diagnose the cause of diarrhea in your cat by reviewing a detailed medical history, performing a physical examination, and in some cases, taking samples for laboratory testing. It can be helpful to document details such as when the diarrhea started, how frequent it is, and what it looks like, and note any changes made to your cat’s diet or environment. To help you prepare this information for your veterinarian, see the handout "Diarrhea Questionnaire for Cats".

"Your veterinarian will likely ask you to bring a fresh fecal sample to your appointment."

Your veterinarian will likely ask you to bring a fresh fecal sample to your appointment. In mild cases of diarrhea, further diagnostic testing may be deferred unless initial treatment fails or if the condition worsens. Additional tests may include blood work, stool and rectal swab samples for parasite examination, DNA testing, bacterial culture, radiographs (X-rays), ultrasound, and endoscopic exam.

How is diarrhea treated?

For otherwise healthy adult cats, your veterinarian may advise you to withhold food for up to 24 hours or to feed small quantities of a veterinary diet for gastrointestinal problems. These diets are specifically formulated with a balance of fibers that feed the good bacteria found in your cat’s intestine and with certain antioxidants that support your cat’s immune system while recovering.

"Anti-diarrheal agents, de-wormers, and/or probiotics may be prescribed."

Anti-diarrheal agents, de-wormers, and/or probiotics (bacteria that support intestinal health) may be prescribed. There are several probiotic products that may be helpful in cats with diarrhea. As the quality and effectiveness of these products are not always known, consult your veterinarian before offering anything to your cat. Many cases of acute diarrhea respond quite readily to this conservative treatment, allowing the body's healing mechanisms to correct the problem, without the initial cause ever being established. As the stools return to normal, your cat's regular diet can usually be transitioned from the prescribed veterinary diet over seven to ten days.

If your cat does not improve within four days, further tests or more aggressive treatment may be needed. Severe or prolonged diarrhea can result in significant dehydration and metabolic disturbances due to fluid loss and your pet may require hospitalization for intravenous fluid therapy or other, more intensive treatments.

What is the prognosis?

The prognosis depends upon the severity of the diarrhea, the specific diagnosis, and your cat’s response to treatment. Most cases of simple diarrhea will make a full recovery, while cats with chronic diarrhea may require dietary management or medication to keep the condition under control.

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