You've noticed while cleaning out your cat's litter box that they've been having diarrhea lately, and you're a little concerned. Millions of pet 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 Diarrhea?

Diarrhea is defined as stool that is softer, looser or more watery than it should be. Cats with diarrhea 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 diarrhea 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 veterinarian.

Symptoms of Diarrhea in Cats

Along with having unhealthy-looking stools (usually loose or watery in appearance), cats with diarrhea 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 Diarrhea

There are many causes of diarrhea. 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 diarrhea.

Other potential causes of diarrhea include:

What to Do If Your Cat Has Diarrhea

  • Assess your cat's behavior. 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 diarrhea 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, diarrhea 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.  In this situation, take your cat to your veterinarian or veterinary hospital right away. Bright red blood or darker tarry stools are also considered an emergency.
  • Finally, note the diarrhea's frequency and appearance so that you can mention it to a veterinarian at the next regular visit.

How Your Veterinarian Determines the Cause

Veterinarians may use several tools to determine the cause of your cat's diarrhea:

  • 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 Diarrhea

Treating diarrhea depends on its underlying cause. There are many available treatments for diarrhea that may be recommended by your veterinarian 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) diarrhea, so your veterinarian will probably assess your cat's nutrition. Depending on what is causing your cat’s diarrhea, your veterinarian may recommend a food with lower fat, richer in complex carbohydrates, and/or with added fiber.

To help cats experiencing chronic diarrhea, veterinarians typically develop multifaceted treatment plans, which can include medication and/or specific food recommendations to avoid aggravating the individual cat’s physiology. Some cats have medical conditions that cannot be outright cured.  In many cases, your veterinarian may recommend a long-term nutritional approach to help support proper digestion throughout the cat’s life. Depending on what is causing your cat’s diarrhea, your veterinarian may recommend a therapeutic cat food that is specially formulated to complement the veterinarian’s treatment plan.

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

Dr. Patty Khuly Dr. Patty Khuly

Dr. Patty Khuly is an award-winning veterinarian known for her independent thinking, her spirited pet advocacy, her passion for the veterinary profession, and her famously irreverent pet health writing.

Dr. K 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 now owns Sunset Animal Clinic, a veterinary practice in Miami, Florida.