Kitten Diarrhoea: What's Upsetting Their Tummy?

This article provides general information only and is not a substitute for personalised veterinary advice. Always speak with your vet about your pet’s individual health needs. Accurate as at 25 September 2026.

Kitten diarrhoea is one of those things that can have pet parents searching for answers in the middle of the night. Some episodes are mild and settle quickly, but diarrhoea can also be a sign of illness that needs vet treatment.

Kittens can also become unwell more quickly than adult cats, so it’s worth knowing what’s normal, what’s not, and when it’s time to call the vet.

Here’s what may be behind your kitten’s diarrhoea, the signs to look out for, and what you can do to help them feel better.

Table of contents

What is kitten diarrhoea?
What causes diarrhoea in kittens?
Signs to pay attention to
When to book an appointment with your vet
How is kitten diarrhoea diagnosed and treated?
Can kitten diarrhoea be prevented?
How kitten insurance can support your kitten’s health and wellbeing

What is kitten diarrhoea?

Diarrhoea means your kitten is passing looser, more watery stools than usual. They may also go more often, and you might notice an unusual colour or smell. It can happen on its own or alongside other signs, such as vomiting or a poor appetite.

Kittens are more prone to digestive upsets than adult cats because their gut and immune systems are still developing. The move from their mother’s milk to solid food, known as weaning, can be a particularly vulnerable time.

What causes diarrhoea in kittens?

There are many possible causes of diarrhoea in kittens, and your vet is best placed to work out what’s behind your kitten’s diarrhoea.

Some common causes include:

Weaning and diet changes: moving from milk to solid food, or switching foods too quickly, can unsettle a kitten’s digestive system.
A gap in immunity: as the protection kittens get from their mother’s milk fades, and before their own immune system and vaccinations catch up, they can be more vulnerable to infections.
Intestinal parasites: parasites such as giardia can affect kittens and are particularly common in multi-cat environments like shelters or breeding catteries.
Viral infections: feline panleukopenia (also known as ‘feline parvovirus’) is a serious illness that can cause diarrhoea and vomiting, and is most dangerous in unvaccinated kittens.
Stress: a new home, travel, or meeting new pets or people can all affect a kitten’s digestion.

Some of these causes are more serious than others, so it’s worth mentioning any diarrhoea in a kitten to your vet, especially if it doesn’t settle quickly.

Signs to pay attention to

If your kitten has diarrhoea, pay attention to any changes in their stools as well as how they’re feeling and behaving.

Signs to look out for include:

Mucus or blood in their stools, or stools that look black and tarry
Vomiting
Refusing food
Low energy or seeming quieter than usual
Signs of dehydration

Kittens have much smaller energy and fluid reserves than adult cats. This means they can become dehydrated, or develop low blood sugar, more quickly when they’re unwell. That’s part of why it’s a good idea not to wait too long to get them checked by a vet.

When to book an appointment with your vet

If your kitten has one loose stool but otherwise seems bright and well, it may settle down on its own.

But it’s time to call your vet if your kitten’s diarrhoea:

Contains blood, or looks black and tarry
Continues into the next day
Comes with a fever, vomiting, or a loss of appetite
Is accompanied by lethargy or signs of dehydration

Vets generally recommend having a kitten with diarrhoea checked sooner rather than later. It can be hard to tell early on whether it’s something mild or something that needs urgent treatment. This is especially true for young, unvaccinated kittens, given the risk of more serious viral infections.

How is kitten diarrhoea diagnosed and treated?

Your vet will usually start with a physical exam and ask about your kitten’s diet, environment, and vaccination history.

Diagnosis

They may also recommend a faecal test to check for parasites such as giardia. Diagnosis can depend on your kitten’s age and how unwell they are, so your vet may recommend further tests if needed.

Treatment

Treatment will depend on what’s found and how unwell your kitten is. It might include fluids to treat or prevent dehydration, medication targeted at a specific parasite or infection if one is identified, or supportive care such as anti-nausea medication if your kitten is also vomiting.

It’s best to avoid giving your kitten any human or over-the-counter medication without checking with your vet first, as some common medicines can be harmful to cats. Your vet can talk you through the most appropriate treatment plan for your kitten.

Can kitten diarrhoea be prevented?

You can’t prevent every cause of kitten diarrhoea, but there’s plenty you can do to help lower the risk:

Keep vaccinations on schedule: core kitten vaccinations, including protection against feline panleukopenia, are generally started from around six to eight weeks of age, with follow-up doses every two to four weeks until at least 16 weeks.
Practise good hygiene: clean litter trays regularly, especially in multi-cat households.
Introduce new foods gradually: sudden diet changes are a common, avoidable trigger of diarrhoea.
Book regular vet checks: routine visits can help pick up on parasites and other issues early.

Speak with your vet about a vaccination and parasite prevention plan that suits your kitten.

How kitten insurance can support your kitten’s health and wellbeing

Working out what’s behind your kitten’s diarrhoea can involve a few different steps, from a vet consultation and faecal testing through to medication or, in more serious cases, ongoing treatment. Pet insurance can help you manage some of these costs, so you can focus on getting your kitten back to their playful self rather than worrying about the bill.

With RSPCA Pet Insurance, you can customise your kitten’s cover, with annual cover limit options up to $35,000, benefit percentage options up to 90%, a zero excess option, and a range of optional extras. Every policy also contributes to vital RSPCA animal welfare initiatives, including rescue, rehab and rehoming efforts. So, while you’re helping to protect your own kitten, you’re also making a difference for animals in need across Australia.

To learn more about how RSPCA Pet Insurance could support you and your kitten with kitten insurance, click here. Or, if you’re ready to take the next step, you can fetch a commitment-free pet insurance quote online.

Disclaimer

As with any insurance, terms, conditions, and exclusions apply. Please read the Product Disclosure Statement to make sure the cover suits your needs.

References

[1] Australian Veterinary Association. Weaning Diarrhoea in Kittens and Puppies. Available from: https://www.ava.com.au/member-updates/weaning-diarrhoea-in-kittens-and-puppies/

[2] Cornell University College of Veterinary Medicine. Diarrhea. Available from: https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/diarrhea

[3] European Advisory Board on Cat Diseases. Guideline for Giardiasis. Available from: https://www.abcdcatsvets.org/guideline-for-giardiasis/

[4] European Advisory Board on Cat Diseases. Guideline for Feline Panleukopenia. Available from: https://www.abcdcatsvets.org/guideline-for-feline-panleukopenia/

[5] RSPCA NSW. Protect Your Cat from Panleukopenia. Available from: https://www.rspcansw.org.au/news-and-updates/protect-your-cat-from-panleukopenia/

[6] RSPCA Victoria. Issues Requiring Medical Help. Available from: https://rspcavic.org/learn/issues-requiring-medical-help/

[7] American Veterinary Medical Association. Feline Panleukopenia. Available from: https://www.avma.org/resources-tools/pet-owners/petcare/feline-panleukopenia

[8] Australian Veterinary Association. Vaccination of Dogs and Cats. Available from: https://ava.com.au/policy-advocacy/policies/companion-animals-health/vaccination-of-dogs-and-cats

Further sources

[1] RSPCA Australia. How should I look after my new kitten? RSPCA Knowledgebase. Available from: https://kb.rspca.org.au/knowledge-base/how-do-i-care-for-my-new-kitten/

FAQs

There are many possible causes. Kitten diarrhoea is often linked to weaning and diet changes, a temporary gap in immunity as protection from their mother’s milk fades, intestinal parasites such as giardia, viral infections, including feline panleukopenia, or the stress of a new environment.

Because some causes are more serious than others, it’s worth mentioning any diarrhoea in a young kitten to your vet.

If your kitten has one loose stool but otherwise seems bright and well, it may settle on its own. But call your vet if the diarrhoea contains blood, looks black and tarry, continues into the next day, or comes with a fever, vomiting, loss of appetite or lethargy. Kittens can become unwell quickly, so it’s best not to wait too long.

Feeding advice depends on your kitten’s age, symptoms, and what’s causing their diarrhoea, so it’s best to check with your vet rather than follow a one-size-fits-all rule. Because kittens have smaller energy and fluid reserves than adult cats, going without food can affect them more quickly. It’s best not to fast your kitten or change their diet without your vet’s guidance, especially if they’re very young or not eating well.

Core kitten <a href=”https://rspcapetinsurance.org.au/pet-talk/what-vaccinations-do-dogs-and-cats-need/”>vaccinations</a>, including protection against feline panleukopenia, help guard against one of the more serious causes of diarrhoea in kittens. Vaccinations are generally started from around six to eight weeks of age, with follow-up doses every two to four weeks until at least 16 weeks. Your vet can advise on the most appropriate schedule for your kitten.