Colin FosterBy Colin Foster

Updated November 2026

Cats get diarrhea for many reasons, from a sudden diet change to a parasite or an infection. In this guide, you will learn the most common causes of why does my cat get diarrhea, how to care for your cat at home for a mild, short episode, and which signs mean you should call a veterinarian right away.

Common Causes of Feline Diarrhea

Most cases fall into a few categories. Diet is the most frequent culprit. Switching food too quickly, eating table scraps, or getting into the trash can upset the digestive tract within hours. Dairy is a common trigger, since many adult cats are lactose intolerant.

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Parasites are the next most likely cause, especially in kittens and outdoor cats. Roundworms, hookworms, giardia and coccidia can all cause loose or watery stools, sometimes with mucus or blood. Infections from bacteria or viruses, stress colitis, food allergies, and ingesting foreign objects also show up regularly.

Stress deserves attention too. A new pet, a move, a visiting houseguest or a changed litter box routine can trigger soft stools in sensitive cats. Pay attention to what changed in the days before the diarrhea started.

How to Check Your Cat’s Stool and Overall Condition

Before deciding what to do, gather a few details. Note how many times your cat has gone, what the stool looks like, and how your cat is acting overall.

  1. Count the episodes over the past 24 hours and note whether the stool is watery, soft, or formed but loose.
  2. Look for blood (red or dark), mucus, or visible worms or worm segments.
  3. Check hydration by gently lifting the skin between the shoulder blades. It should snap back quickly.
  4. Watch for vomiting, lethargy, fever signs, straining, or refusal to eat or drink.
  5. List any recent food changes, new treats, plants, medications, or household changes.

Home Care for Mild Diarrhea

If your cat is bright, eating, drinking, and has only one or two loose stools with no blood, you can often manage it at home for a short period. Withhold treats and new foods, and offer a small amount of their regular diet. Make sure fresh water is always available. Some owners find that a bland, easily digested food helps stools firm up, but introduce it gradually and do not switch foods abruptly.

Do not give human anti-diarrheal medications unless a veterinarian tells you to. Many are toxic to cats. Keep the litter box clean so you can monitor stool changes accurately.

When Home Care Is Not Enough

Diarrhea lasting more than 24 to 48 hours, or any episode in a kitten, senior cat, or cat with a chronic condition, warrants a call to your vet. Dehydration can become serious quickly in cats, especially those who are already weak.

Warning Signs That Need a Vet Visit Now

Contact a veterinarian promptly if you notice any of the following:

  • Blood in the stool or black, tarry stool
  • Repeated vomiting along with diarrhea
  • Lethargy, weakness, or hiding
  • Signs of dehydration, such as dry gums or slow skin rebound
  • Diarrhea in a kitten under six months old
  • Suspected toxin exposure, such as a plant, medication, or household chemical

Consult a veterinarian for any cat with persistent or severe symptoms. A vet can run a fecal test, check hydration, and recommend treatment specific to your cat’s condition.

Preventing Future Diarrhea Episodes

Prevention focuses on consistency and parasite control. Transition new foods over seven to ten days by mixing a small amount of the new food into the old, increasing the ratio gradually. Keep your cat on a regular deworming and parasite prevention schedule recommended by your vet. Restrict access to trash, spoiled food and plants, and keep your cat’s routine as stable as possible during household changes.

If your cat has recurring soft stools, review diet and stress triggers with your vet. Learning more about broader feeding choices can help, such as the differences covered in Wet vs. Dry Cat Food: Pros, Cons, and Differences. Changes in eating habits can also signal a deeper issue, so it is worth reading Why Your Cat's Appetite Has Suddenly Changed if you notice both symptoms together.

Common Mistakes

  • Switching foods abruptly, which is one of the most frequent triggers of diarrhea.
  • Giving human medications such as Pepto-Bismol or loperamide without vet approval.
  • Ignoring symptoms for several days while the cat becomes dehydrated.
  • Assuming all diarrhea is a food problem and skipping a fecal test.
  • Offering milk as a treat, since most adult cats cannot digest it well.

A clean, shallow litter box makes it easier to spot changes in stool. Choose one with low sides so your cat can get in and out quickly if they are straining or urgent. View on Amazon

A digital kitchen scale helps you measure portions exactly when transitioning foods or feeding a sensitive cat. View on Amazon

FAQ

Can stress alone cause diarrhea in cats?

Yes. Stress colitis is a recognized cause of soft or watery stools, often following a move, a new pet, or a change in routine. Symptoms usually improve once the stressor is reduced, but a vet should still rule out other causes.

Is it safe to fast my cat when they have diarrhea?

No. Cats can develop serious liver problems if they stop eating for too long. Offer small, regular meals of their usual food and check with your vet before withholding food for more than a short period.

How long should cat diarrhea last before I call the vet?

Call your vet if diarrhea lasts more than 24 to 48 hours, or sooner if your cat is a kitten, senior, weak, vomiting, or showing blood in the stool.

Conclusion

Diarrhea in cats has many possible causes, from diet changes to parasites and stress. Mild, short episodes in an otherwise healthy adult cat can often be managed at home with careful observation and a steady diet. Any warning sign, especially blood, lethargy, or dehydration, means you should contact your veterinarian without delay.

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Colin Foster

About Colin Foster

Colin Foster is part of our editorial team and reviews and edits our cats guides, checking product details against manufacturer specifications and owner feedback.