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You've noticed while cleaning out your cat's litter box that they've been having diarrhoea lately, and you're a little concerned. Millions of cat parents witness this same issue with their cats every year. Whether your cat's version is the soft and gooey variety, the streaky bloody style or the unfortunately watery kind, you can be sure you're not alone in your litter box observations.

What is Cat Diarrhoea?

Diarrhoea is defined as stool that is softer, looser or more watery than it should be. Cats with diarrhoea may defecate more frequently than usual, have accidents in the house, and may pass blood, mucus or even parasites in their feces.

Though most cases of cat diarrhoea resolve in a matter of hours or days without intervention, cats who have it for more than a few days, or that show more severe signs (such as vomiting, appetite loss, bloody stools, watery stools or tiredness), should be seen by a veterinarian immediately.

It's important to note that smaller cats and kittens with diarrhea are especially susceptible to dehydration, so they should always be evaluated by a vet.

Persian cat standing in white litter tray on tile floor.

Symptoms of Diarrhoea in Cats

Along with having unhealthy-looking stools (usually loose or watery in appearance), cats with diarrhoea may have the following symptoms:

  • Mucus or blood in the stool
  • Worms in the stool
  • Accidents in the house
  • Defecating with increased frequency
  • Straining to defecate
  • Nausea or vomiting
  • Loss of appetite
  • Tiredness or weakness
  • Abdominal pain
  • Weight loss

Causes of Cat Diarrhoea

There are many causes of diarrhoea. Often it occurs when a cat eats something unusual or when their meal plan changes abruptly. When switching from one kind of cat food to another, it's best to transition slowly over a week, gradually mixing in more of the new food and less of the old food. This transition allows the pet's digestive system to adjust and lowers the chance of diarrhoea.

Other potential causes of diarrhoea include:

  • Viruses
  • Parasites
  • Bacterial overgrowth in the digestive tract
  • Food allergies
  • Inflammatory bowel disease
  • Antibiotics and other drugs
  • Toxins
  • Pancreatitis
  • Liver disease
  • Hyperthyroidism
  • Cancer

What to Do If Your Cat Has Diarrhoea

Assess your cat's behaviour. Do they appear to be feeling well or acting more tired than normal? Do they have a poor appetite or any other symptoms that stray from their norm? Are they also vomiting? If a case of cat diarrhoea is an isolated incident that resolves spontaneously in less than a few hours and doesn't involve other symptoms, it's generally not treated as an emergency.

However, diarrhoea over a prolonged period (more than a day), as well as diarrhea accompanied by a significant change in demeanor or other signs, should be treated as an emergency and taken to their vet or vet hospital right away. Bright red blood or darker tarry stools are also considered an emergency.

Finally, note the diarrhoea's frequency and appearance so that you can mention it to a vet at the next regular visit.

How Your Vet Determines the Cause

Vets may use several tools to determine the cause of your cat's diarrhoea:

  • The cat's medical history
  • A physical examination
  • Basic lab work (blood work, fecal exam)
  • X-rays (radiography)
  • Gastrointestinal function tests (blood tests)
  • Endoscopy/colonoscopy and biopsy (to retrieve a tissue sample)
  • Medication trials (assessing a response to medication)
  • Food trials (assessing a response to certain foods)

Treatments & How Nutrition Impacts Diarrhoea

Treating diarrhoea depends on its underlying cause. There are many available treatments for diarrhoea that may be recommended by your vet depending on a variety of factors. However, nutrition plays a key role in managing this condition.

Nutrition plays a significant role in a healthy cat stool. Poor nutrition may lead to chronic (ongoing) diarrhoea, so an assessment of your cat's nutrition will be conducted by your vet. They may recommend switching cat foods as a course of treatment. A lower-fat food or food richer in complex carbohydrates and digestible complex carbohydrates with added fiber may be recommended.

Chronic cases of diarrhoea are typically treated with special meal plans alongside medications. In many cases, your veterinarian will recommend nutritional therapy for the rest of the cat's life to help maintain proper digestion for conditions that cannot be outright cured. Your vet may recommend a therapeutic cat food that is specially formulated to help with digestion and diarrhoea. Many cases of chronic GI disease in cats respond well to a highly digestible food with added prebiotic fibers. This category of GI disease is called 'food-responsive enteropathy.

In cases where food allergies are a concern, a series of nutritional trials may be necessary to determine the cat's ideal meal plan. Hydrolyzed foods or novel protein foods are commonly recommended for these cats.

While cat diarrhoea is unfortunate, with the right treatment and help from your veterinarian your cat can get back to the happy, healthy self.

Hill’s Prescription Diet Gastrointestinal Biome food for dogs and cats is clinically proven to help promote healthy stool in as little as 24 hours. This first-of-its-kind nutrition, made with Active Biome+ ingredient technology, nourishes the gut microbiome to support a pet's digestive health. Speak to your veterinarian or visit for more information.

Contributor Bio

Dr. Patty Khuly

Dr. Patty Khuly is an honors graduate of both Wellesley College and the University of Pennsylvania School of Veterinary Medicine. She received her MBA at The Wharton School of Business as part of the prestigious VMD/MBA dual-degree program. She's now the proud owner of Sunset Animal Clinic in Miami, Florida. But that's not all. Dr. K is a nerdy reader, avid knitter, hot yoga fanatic, music geek, struggling runner, and indefatigable foodie. She lives in South Miami with three dogs, countless cats, two rescued goats and a hilarious flock of hens.

You can follow her writing at and at

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