Colin FosterBy Colin Foster

Updated November 2026

If you’re asking why does my cat has diarrhea, the short answer is that most cases come from diet changes, stress, parasites, or something your cat ate. This guide will help you narrow down the likely cause, handle mild cases at home safely, and recognize the signs that mean you should call a veterinarian right away.

Common Causes of Cat Diarrhea

Diarrhea is a symptom, not a disease, so the cause matters. Cats often develop loose stools for a handful of predictable reasons.

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  • Sudden diet change. Switching food brands or flavors too quickly upsets the gut bacteria.
  • Eating something unusual. Garbage, houseplants, grass, human food, or rich table scraps can irritate the intestines.
  • Intestinal parasites. Roundworms, hookworms, tapeworms, Giardia, and coccidia are common, especially in kittens and outdoor cats.
  • Stress. Moving, new pets, boarding, or a new baby in the home can trigger loose stools.
  • Food intolerance or allergy. Some cats react to specific proteins or ingredients.
  • Infections or illness. Bacterial or viral infections, pancreatitis, inflammatory bowel disease, and kidney or thyroid problems can all cause diarrhea.

How to Tell Mild From Serious Diarrhea

Watch the stool and your cat’s overall behavior for the first 24 hours. Mild, single-episode diarrhea in an otherwise bright, eating cat often resolves on its own. Persistent or bloody diarrhea does not.

Situation What it usually means What to do
One or two soft stools, cat eating and playing normally Mild upset, likely diet or stress Monitor closely for 24 hours
Diarrhea lasting more than 24 hours Possible infection, parasites, or GI disease Call your vet
Blood, black or tarry stool, or mucus Possible bleeding or serious inflammation Call your vet promptly
Vomiting, lethargy, or refusing food alongside diarrhea Risk of dehydration or systemic illness Seek veterinary care the same day

What to Do at Home

For mild cases in an otherwise healthy adult cat, these steps can help while you watch for changes.

  1. Withhold treats and new foods for about 12 hours, but do not starve your cat for more than that.
  2. Make sure fresh water is always available. Consider a fountain or extra bowls to encourage drinking.
  3. After the gut settles, offer a small amount of your cat’s usual food. If you’re switching foods, do it gradually over 7 to 10 days.
  4. Keep a simple log of stool consistency, appetite, water intake, and litter box visits. This is useful if you do call the vet.
  5. Check the litter box and your cat’s rear end for signs of parasites such as small rice-like segments.

Never give human anti-diarrheal medicine to a cat unless your veterinarian tells you to. Many common human drugs are toxic to cats.

Preventing Future Episodes

Prevention focuses on keeping the gut stable. Feed meals at consistent times, change foods gradually, and keep your cat away from garbage and toxic plants. Deworm and parasite-test on the schedule your vet recommends, especially if your cat goes outdoors. Stress-related diarrhea often improves when your cat has a quiet hiding spot and a predictable routine. If your cat also shows changes in appetite, see Why Your Cat’s Appetite Has Suddenly Changed for related warning signs.

Common Mistakes

  • Switching to a new food every few days while trying to find a fix.
  • Assuming diarrhea is harmless in kittens or senior cats, who dehydrate faster.
  • Waiting too long when there is blood in the stool or your cat stops eating.
  • Using over-the-counter medication without veterinary guidance.
  • Ignoring litter box changes. If your cat also begins avoiding the box, read Why Cats Stop Using the Litter Box and How to Respond.

A few simple supplies make monitoring easier and reduce mess during an episode.

  • Cat water fountain. Many cats drink more from moving water, which supports hydration during loose stools. View on Amazon
  • Unscented, clumping cat litter. It makes stool changes easier to see and clean. View on Amazon
  • Enzymatic pet stain and odor remover. It cleans accidents thoroughly so your cat isn’t drawn back to the same spot. View on Amazon

FAQ

Is cat diarrhea an emergency?

It can be. Call a veterinarian the same day if your cat has blood in the stool, vomiting, extreme lethargy, or signs of dehydration such as dry gums or skin that stays tented when lifted.

How long can diarrhea last before I should worry?

If loose stools continue beyond 24 hours, or your cat seems unwell, contact your vet. Kittens and older cats should be seen sooner.

Can I feed plain rice or pumpkin to my cat?

Some vets suggest small amounts of plain, cooked food or plain canned pumpkin for mild cases, but ask your veterinarian first, especially for kittens, diabetic cats, or cats with existing conditions.

Conclusion

Cat diarrhea usually traces back to diet, stress, parasites, or something eaten, and many mild cases clear up within a day. Track your cat’s symptoms, keep them hydrated, and call your vet if the problem lasts, includes blood, or comes with other signs of illness. This article is general guidance and does not replace professional veterinary care.

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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.