7 Reasons Cats Have Diarrhea and How to Fix It

Written by Amber LaRock
Updated: September 30, 2023
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If you have just found diarrhea in your cat’s litter box, you are likely concerned about your little one’s health. You may wonder what could have caused this sudden shift in their gastrointestinal health, and what you can do to help them feel better.

In this article we’ll give you the tools needed to better understand your cat’s sudden case of diarrhea, and how you can help your little one get back in track.

Let’s dive in!

Is Diarrhea In Cats A Big Deal?

Cat's face being stroked by woman's hand

Diarrhea that lasts for more than 24 hours in cats can lead to dehydration.


Diarrhea may not seem like a big deal, but it can lead to serious health complications. A cat with diarrhea is losing an increased amount of body fluid each time they pass stool, so this can quickly lead to dehydration. A mild case of diarrhea that resolves within 24 hours is not often the end of the world, but a case of diarrhea that last for more than 24 hours should always be taken seriously.

Dr. Amy Nicole Lewis, a veterinarian with Worldwide Veterinary Services told A-Z Animals that diarrhea and vomiting are the most common factors leading to hospitalization in pets. The excessive water loss from severe GI upset puts your pet at risk of life-threatening dehydration, and many require IV hydration to restore this fluid loss.

7 Reasons Why Cats Have Diarrhea

ragdoll kitten playing under the covers

Diarrhea in cats can develop due to diet changes, bacterial infections, intestinal parasites, and more!

©iStock.com/Angela Kotsell

Let’s break down the most common causes of diarrhea in cats below!

#1 Sudden Diet Changes

A sudden change in your cat’s diet can lead to gastrointestinal upset and diarrhea. Unlike us, our feline friends tend to eat the same thing every day. The microbiome and digestive enzymes in their gut have become accustomed to the food they eat, so when their is an abrupt diet change, it essentially shocks the system. A sudden change in diet can lead to an inflammatory response in the digestive tract, resulting in diarrhea and vomiting. This is why it is so important to introduce a new diet to your cat over a two-week period.

#2 Stress & Anxiety

Most cats are creatures of habit, so any changes in their environment can trigger stress or anxiety. Even the smallest of changes can lead to anxiety in your feline friend, causing them to experience stress-related health complications. Stress in cats can cause a release of the fight or flight hormone named norepinephrine, and this can speed up their standard digestion process. Fast moving intestines often lead to diarrhea and soft stool.

#3 Exposure To Bacteria

Bacteria exists everywhere in the world around our feline friends. Our cats can be exposed to this bacteria by eating spoiled food, eating something strange outside, and even in unsanitary food and water bowls. If this bacteria has a chance to enter their digestive system and replicate, this can quickly lead to a case of diarrhea.

#4 Intestinal Parasites

Intestinal parasites are a common cause of diarrhea in cats, especially kittens or cats that spend time outdoors. Intestinal parasites are incredibly destructive to the GI tract, leaving a trail of inflammation in their wake. Some of the intestinal parasites that can cause severe diarrhea in cats include roundworms, hookworms, tapeworms, coccidia, and whipworms. Your cat may also experience weight loss, vomiting. bloody stool, changes in appetite, lethargy, abdominal swelling, and pale gums.

#5 Infectious Illnesses

Infectious illnesses like panleukopenia and coronavirus can lead to severe diarrhea in our feline friends. The cats most at risk of these infections are kittens under one year of age, unvaccinated cats, cats that go outdoors, and cats that live in shelters or rescues. These illnesses can also cause vomiting, bloody stool, decreased appetite, lethargy, weight loss, dehydration, and low blood sugar.

#6 Toxicities

There are many items in our home that can be toxic to cats. This can include toxic human food, human medications, plants, cleaning supplies, essential oils, and more. While each toxicity can cause their own symptoms, diarrhea and vomiting is commonly seen in these situations. We always suggest reaching out to your vet immediately if you think your cat has been exposed to something toxic.

#7 Underlying or Chronic Health Issues

Chronic diarrhea can be a sign of a variety of underling medical conditions. Let’s list a few of the health complications that lead to GI upset in cats below:

  • Inflammatory bowel disease
  • Pancreatitis
  • Kidney disease
  • Food allergies
  • Hyperthyroidism
  • Diabetes
  • Cancer

Diarrhea that lasts for more than 24 hours should always warrant a vet visit to rule out any underlying medical conditions.

When Should I Be Worried About My Cat’s Diarrhea?

As we mentioned above, we always suggest reaching out to your vet if your cat’s diarrhea has persisted for over 24 hours. This is especially true if they are displaying other changes in behavior such as a decreased appetite, lethargy, vomiting, weight loss, and any other changes in behavior. No matter the cause of your cat’s diarrhea, it can quickly lead to dehydration if left untreated for too long.

How To Fix Diarrhea In Cats

cat at the vet being examined

Diarrhea in cats can lead to dehydration if left untreated for too long. It’s best to reach out to your vet if your cat’s diarrhea persists for more than 24 hours.

©Beach Creatives/Shutterstock.com

Now that you have a better understanding of why cats have diarrhea, let’s discuss the most effective ways to treat it!

Reach Out To Your Vet For Guidance

The first thing you should do when your cat develops a case of diarrhea is reach out to your vet for guidance. They can offer the best guidance based on your cat’s medical history and their current symptoms, and they can even offer you support on how to manage their symptoms from home. Reaching out to your vet first is always best, as your little one’s current symptoms may require medical care.

Monitor Them Closely & Look For Other Symptoms

It’s important to monitor your cat closely if they ever develop diarrhea. You will want to be on the lookout for any changes in appetite, any sign of lethargy, and vomiting, and just how long their diarrhea lasts. If their diarrhea resolves within 24 hours, then it may have just been a mild case of GI upset that just needed time, However, if their diarrhea persists or they develop any other GI symptoms, then they likely need to be assessed in person by your vet.

Switch Them Over To A Bland Diet

Mild GI upset in cats can be resolved in some cases by switching them over to a bland diet. This is most effective in cats that developed diarrhea due to bacterial infections, stress, or even abrupt diet changes. A bland diet of boiled chicken breast and white rice can offer their digestive tract the break it needs to heal.

It’s important to keep in mind that a bland diet will not resolve diarrhea in cats with intestinal parasites, infectious disease, or other undiagnosed medical conditions.

Offer Them Feline Probiotics

Probiotics for cats can be added to a bland diet to resolve mild GI upset in cats. The natural flora that lives within your cat’s GI tract can be thrown off due to things like stress and diet changes, so the good bacteria in probiotics can help to restore this imbalance.

Final Thoughts On Diarrhea In Cats

Diarrhea in cats can be a result of diet changes, stress, bacteria, intestinal parasites, infectious illnesses, and a variety of underlying medical conditions. If your cat’s diarrhea persists for more than 24 hours, then we suggest reaching out to your veterinary team for guidance on what to do next.

The photo featured at the top of this post is © Africa Studio/Shutterstock.com

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About the Author

Amber LaRock is a writer at A-Z Animals primarily covering topics surrounding pet health and behavior. Amber is a Licensed Veterinary Technician with 12 years of experience in the field, and she holds a degree in veterinary technology that she earned in 2015. A resident of Chiang Mai, Thailand, Amber enjoys volunteering with animal rescues, reading, and taking care of her two cats.

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