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Pet Resources
Feline Diarrhea & Questionnaire

What is diarrhea?

Diarrhea is the passage of feces as unformed or loose stools, usually in increased volume and frequency of passage. It is a result of increased speed of passage of fecal material through the intestine combined with decreased absorption of water, nutrients and electrolytes. There are many causes of diarrhea. Diarrhea may occur as the only sign or in combination with other signs of more widespread disease, or with symptoms 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. But if the cat is still using the litter box and covering up its feces or defecates outdoors, it may be difficult to initially notice diarrhea. Staining and soiling of the fur around the back end in long-haired breeds is often associated with diarrhea. It is important to remember that some variation in the consistency of stools is not unusual. Changes in diet can lead to temporary changes in the stool. If frequent liquid or semi-liquid stools persist for more than two days, you should consult your veterinarian. If there are more general signs of illness in your cat, then call your veterinarian immediately. If you have more than one cat then it is important to try and determine if it is just one cat or if other cats also have diarrhea.

What are some causes of diarrhea?

Diarrhea is not a disease in itself but a clinical sign that may reflect one or more of many different problems. Most involve some degree of inflammation of one or more sections of the alimentary or gastro-intestinal (GI) tract. The GI tract is the continuous tube that carries food from mouth to anus. Inflammation can be caused by infectious agents such as bacteria, viruses, coccidia, and intestinal worms, or by non-infectious irritants such as chemical toxins, poisonous plants, and so on. Allergies to certain specific components of a diet may be responsible for diarrhea. Diarrhea may occur as a sole symptom or as one of several symptoms of a more generalized disease problem.

How is the cause of diarrhea determined?

It is important to provide your veterinarian with a detailed medical history. Ideally you should write this out in chronological order before you go to the clinic. Be as detailed as possible on the date you first noticed a problem, even in retrospect. Also report the progression of the clinical signs. Note any changes in the normal routine of your cat or your household. How frequent are the stools? What is the color, consistency, and smell of the feces? Is the cat showing any other signs such as vomiting, loss of appetite, lethargy, or loss of weight? We have a checklist to help you put this history together.

Besides a thorough clinical exam, your veterinarian may recommend additional diagnostic tests. These tests may be deferred in mild cases of diarrhea unless initial treatment fails or the condition worsens. Tests may include blood work, stool and rectal swab samples for parasite examination and culture, radiographs, and endoscope exam.

How is diarrhea treated?

Initially, and often in advance of in-depth work-up, a non-specific approach may be adopted. It is a good idea to withhold food for twenty-four hours and encourage water consumption. Gradually reintroduce small quantities of a light, easily digestible diet. Boiled rice or other pasta with some boiled skinless chicken may be given if a special veterinary diet is not available. Anti-diarrheal medication may be used to help speed your pet's recovery. Many cases of diarrhea will respond quite readily to simple treatment, without the initial cause ever being established. As the stools return to normal, the cat's regular diet can be gradually reintroduced, mixed initially with the bland rice-chicken or similar diet.

If there is little or no improvement over two or three days, if the cat is not taking any water or if the cat's health worsens, then your veterinarian should be notified at once. Treatment may be more aggressive based on the results of an in-depth clinical work-up as outlined above. Loss of fluid is one of the most serious aspects of severe or prolonged diarrhea, and if vomiting is present, dehydration can rapidly escalate. Correcting the dehydration may require intravenous or subcutaneous fluids.

Can I use anti-diarrheal medications from the human pharmacy?

Some of the preparations recommended for people are very dangerous for cats so never use a medication without consulting your veterinarian first. Products containing ASA or acetaminophen are extremely toxic in cats.

My cat has chronic diarrhea. Will it get better?

Chronic diarrhea that has been present for two to three weeks or longer may prove more difficult to diagnose and to treat effectively. Even extensive work-up does not always provide a definitive answer to the problem. But in many cases a thorough clinical work-up, including food trials, can result in a successful outcome.


In order for us to narrow down the cause of diarrhea in your cat, please answer the following questions as accurately as possible and bring this information with you to your pet's appointment. If you are not certain about the answer please indicate "approximately" or "not sure".


Look at a calendar and try and determine the earliest date when you remember noticing unusual stools from your cat.

  • On the calendar note any other changes in the cat's routine or household routine

Frequency and nature of stools, feces, bowel movements

  • How frequently is the cat having bowel movements?
  • Are the stools semi-formed, unformed, or liquid?
  • What is the dominant color (yellow, brown, black, etc.)?
  • Is there any suggestion of blood (fresh=red or changed=tarry black)?
  • Is there mucus (that often looks like egg white) in the stool?
  • Is there undigested food present in the stool?
  • How powerful is the smell?


  • What is the cat's normal diet?
  • Has the diet changed within the past two months?
  • Do you feed your cat milk?
  • Did you feed your cat table scraps within the past two weeks? If so, what?
  • Has the cat stolen any food recently?
  • Does the cat hunt and eat its prey?
  • Does the cat take food from anywhere else such as from a neighbor?

General health

  • When was your cat last vaccinated? If at another clinic, do you have the medical records?
  • Are there any other signs of illness?
  • When did you first notice any other signs of illness?
  • Has there been any weight loss? If so, over what period?
  • How is your cat's appetite?
  • Have you seen any vomiting?
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