What Causes Diarrhea in Cats?

Checking your cats litter box can help indicate whether your not your cat could be sick. Find out what causes diarrhea in cats and how to prevent it.

Denise LeBeau  |  Jul 10th 2019


One of the stickiest subjects regarding feline health is diarrhea. Your cat’s poop is a strong indicator of whether your cat has an illness or an injury, and taking a minute to double check the contents of the litter box is always a good idea. Abnormalities like blood in cat poop or a loose stool can be the symptom of some major underlying issues. Or not! Let’s find out what causes diarrhea in cats.

Common causes of diarrhea in cats

It’s important to remember that diarrhea is not a disease unto itself but a symptom! There is a gamut of reasons why your cat may be having a bout of diarrhea. First off, diarrhea is the condition where the cat’s poop is anywhere from very soft and runny masses to just liquid. The scale ranges from the consistency of soft-serve ice cream to puddles. Normal cat poop is usually akin to a Tootsie Roll – so, firm. Depending on the cat’s diet – maybe it’s strictly wet cat food or a raw diet versus an all kibble menu – determines the cat’s poop consistency baseline for what is normal for him.

According to Dr. Will Spanbock of Good Ground Animal Hospital in Hampton Bays, New York, there are a few usual culprits for diarrhea in cats.

Here are Dr. Spanbock’s top 4 reasons for diarrhea in cats:

  1. Dietary Indiscretion. This amounts to eating something that upsets the digestive system. The American Veterinary Medical Association list for the most toxic household items to cats is comprehensive (some are surprising, like coffee grounds, grapes, onions, garlic and anything with artificial sweetener).
  2. Infection. Different types of infections can cause diarrhea. Maladies such as Intestinal Viral Infection (rotavirus, which is transmitted through fecal matter), or any of the variety of bacterial, viral or fungal infections could be the culprit.
  3. Inflammatory Bowel Disease. Determining what exactly is the root cause for IBD requires a battery of tests, but one of the most common symptoms is diarrhea. This is usually the result of a bowel that has thickened and is inflamed.
  4. Parasites. Tapeworms, hookworms, coccidia and Giardia are often responsible for a sudden explosion of diarrhea. The Companion Animal Parasite Council is a great resource to see what infliction is most prevalent in your area – and additional expert advice on the subject.

Treating diarrhea

Getting your cat treated for diarrhea is important if it continues for more than 24 to 48 hours. Most of the time diarrhea corrects itself. Sometimes putting the feline on a blander diet can clear it up. Minor disagreeable disruptions to his digestive system usually subside fairly quickly. However, if the condition continues, or if it’s accompanied with your cat throwing up or showing signs of dry heaves, he must go to the veterinarian immediately.

It’s important to note that you should not try to fix your cat’s diarrhea problem with over-the-counter medication. Medications for your cat should strictly be administered under the guidance of your veterinarian.

The following are items that should be in hand when you visit the animal medical professionals:

  1. A fresh stool sample.
  2. A list of what he’s eaten in the last two weeks.
  3. Notes regarding anything that’s been different in his life recently. (Did he get out accidentally? Has there been a change in routine? Have you noticed any lethargy or increase/decrease in appetite? Did you change cleaning supplies? And so on…)

Best practices

  • To best avoid diarrhea, consistency in his diet is key. If you’d like to change his food, do it gradually. Feeding your cat a premium diet is good for his overall health and mitigates the chances of diarrhea.
  • Make your cat an indoor-only cat. Of course, a controlled environment provided by a catio is the perfect way to give him access to nature but will keep him safe.
  • Get him his annual check up.  Check him periodically for any abnormalities. Look in his mouth and his ears. Run your hands over his body daily, feeling for any lumps or bumps that may have cropped up. You are the best line of defense for keeping your cat free from illnesses or catching an injury quickly.
  • Don’t forget parasite prevention! Avoiding fleas, ticks and heartworm is worth 10 pounds of cure – the upside to preventing an infestation is paramount to your cat’s health and well-being. Do not wait until kitty is facing a life-altering situation to address these pests.

All in all, cat diarrhea can be nothing serious or it can be the sign of illness, injury or infestation that can be deadly. Observing your cat’s poop and overall demeanor, and whisking him to the vet right away if the issue persists, will keep him healthy!

About the author:

Denise LeBeau is a writer, editor and photographer with almost 20 years of experience of creating content for animal-related issues, endeavors and events. She worked at Best Friends Animal Society for 12 years where she had two columns in the Best Friends Magazine, and held multiple content creation roles including web managing editor and outreach campaign editor. Denise has been an ongoing contributor to Catster since 2014, writing for the magazine and website. The self-professed poet laureate of the pet set is currently the manager of development for an animal welfare agency, where she works with a team to create content across media platforms. She lives in Hampton Bays with her two rescue Siamese mixes – Flipper and Slayer, and her LBD (little brown dog), Zephyrella.

Learn more about diarrhea and other health issues in cats on catster.com: