Giardia in cats

Giardia in cats can be challenging to treat but it’s usually not a life-threatening disease. Cats younger than 3 years old are more likely to have this infection.

Giardia is a tiny parasite that causes upset tummies. It carries a low risk of spreading to humans, but it’s recommended to practise good hand and house hygiene when handling your cat with giardiasis.



What is giardia in cats?

  • Giardia is a one-celled parasite, not a worm, bacteria, or virus.
  • This parasite sticks to its host’s gut to feed itself.
  • It can infect cats and cause watery diarrhoea.
  • Humans and other animals, such as dogs, can catch giardia.
  • Giardiasis is the name of the disease caused by the parasite giardia.

shutterstock 2126984780 1

How do cats get giardiasis?

Your cat can catch giardia by:

  • Being in contact with infected poo from another animal.
  • Rolling and playing in contaminated soil and grass.
  • Licking their own fur and body after contact with a contaminated surface.
  • Drinking water from a contaminated creek, pond, or others.



Symptoms of giardia in cats

Symptoms of giardiasis normally begin 1 to 2 weeks after becoming infected.

Signs include:

  • Strong smelling, watery diarrhoea
  • Diarrhoea sometimes containing mucous
  • Farting (flatulence)
  • Eating less
  • Vomiting



Are some cats more likely to show giardia symptoms?

Younger cats or those with weakened immune systems are more likely to experience symptoms of a giardia infection.



How is giardia in cats diagnosed?

To diagnose giardia, your vet will need to examine a stool sample.

Because giardia can be shed intermittently in the stool, it might not be seen on a single stool sample. So your vets may request that you collect samples for 3 to 5 days.

Your vet may perform a second stool test, such as Giardia-specific antigens, to help detect specific proteins from the parasite.

shutterstock 1229898391 1

How to collect a poo sample

  • Usually, your vet provides you with a poo sample container that comes with a spoon attached to it.
  • Or you may use a clean container, like tupperware or a poobag.
  • When possible, wear gloves when touching the stool. If not, wash your hands thoroughly immediately afterwards.
  • Collect around two scoops of poo, close it, and label it with your pet’s details.
  • The samples need to be stored in the fridge.
  • But to avoid any food contamination, put the sample into another bigger container before you place it in the fridge.
  • Repeat this process for another 2 or 4 days, as requested by your vet.
  • You may store the stools in different containers each day, or you may place them all in the same container.
  • When the collection is complete, take it to your vet practice.

shutterstock 1719987358 1


Vet treatment

What’s the treatment for giardia in cats?

Giardia infections can be difficult to resolve. The goal of treatment is to stop the diarrhoea and other signs that your cat may have.

Your vets will discuss treatment with you and will include environmental management instructions. See the next section for more information.


  • Fenbendazole is a common deworming medication used to treat giardia.
  • Metronidazole is an antibiotic that is also used as a treatment option.
  • Your vet may use the two medications in combination.


  • Your vet may prescribe a diet that supports digestive health to help resolve diarrhoea, such as Hill’s Prescription Diet i/d.
  • They may also add a probiotic.

It typically takes at least a couple of weeks of treatment and strict environmental management to clear the disease.


Home treatment

What you need to do at home to treat your cat with giardia

Environmental and hygiene management of your home and pets is very important not only to treat this disease but also to prevent re-infection. Take the following actions:

Environmental cleaning:

  • Common household disinfectants are the most effective ways to kill giardia.
  • Clean your house regularly.
  • Remove and dispose of all poo without delay.
  • Giardia on the lawn can only be killed by direct sunlight, which dries them up.
  • To kill giardia on a concrete surface, perform basic cleaning before disinfecting.

Hair coat cleaning:

  • Try to keep your cat clean, especially around the backend. You can do this by using animal disinfectant wipes.



How to prevent and control giardia in cats

Preventing and controlling giardiasis can be a difficult task. Giardia can persist on animals fur and in the environment for months, even after the original poo has gone.

Some steps can help decrease, but not eliminate, the risk of reinfection to your cat or transmission to other animals:

  • Do not miss any doses of the medication given by your vet.
  • Clean the floor in your home daily.
  • Regularly clean any potentially contaminated items, such as: toys, water and food bowls, pet bedding, litter box, bedding.
  • Regularly clean any outdoor surfaces.
  • Continue cleaning until a few days after the last dose of medication is given.
  • Limit your cat’s access to the outdoors in order to avoid re-infecting themselves or spreading infection to other animals.

Can your cat pass giardia on to your family?

The chances of people getting a giardia infection from dogs or cats are low. The type of giardia that infects humans is not usually the same type that infects dogs and cats.

However, maintenance of good hygiene practices, such as regular hand-washing is important.


When to worry

When to worry about your cat with giardia

Seek help from a vet practice if your cat:

  • Has vomiting and diarrhoea and is looking unwell
  • Looks bloated
  • Is still vomiting despite your vet’s treatment
  • Passes poo that is covered in blood or has specks of blood for more than one day
  • Is in pain

Joii can help if:

  • Your cat is well but not interested in food or water
  • You want to discuss feeding
  • Your cat has one poo with specks of blood
  • You need help with hygiene management
Consult a vet - £28

Consult your vet online. Anyday, anytime.

Consult a Joii vet online for £28. Or free if you’re insured with one of our partners.

Developed by vets 🩺

QR code to app

How to get an

Join a practice

*It's free*

Download the app to register and become a member of Joii vets. In only a few taps you will have access to digital vet care 24/7 as well as a vet practice

Download the app

We’re writing as quick as we can

This article is currently being written by one of our expert vets. Check back soon.