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Fleas on cats

cat on white background


  • Fleas are tiny insects that can live on dogs, cats, rabbits and in your home.
  • Fleas cause itchy skin, spread disease and can bite humans.
  • Some cats are allergic to flea bites and suffer severe irritation every time they are bitten.
  • Fleas feed on blood and can cause anaemia (significant blood loss) in young, old or ill pets.
  • Preventing fleas is easy – use a licensed veterinary flea product regularly.
  • WARNING: Some flea treatments for dogs are highly toxic to cats.

Covid-19 update

At the moment, your veterinary practice might not be able to dispense your cat’s usual prescription flea treatment. Non-prescription products might be available online and from pet shops, which you may need to consider using until your vet is operating a full service again.

If you are concerned, or your pet has a specific condition which requires a prescription flea treatment, contact your vet to discuss what to do.

Never use a dog flea treatment on a cat.

How to tell if your cat has fleas

If your cat has fleas, you may notice the following symptoms:

  • Scratching
  • Flea dirt (often on the lower back)
  • Bites or a rash
  • Alopecia (bald patches) or rough/spikey fur
  • Wounds and infected skin
  • Enjoying scratches more than usual because they are so itchy
  • Turning quickly or jumping to nibble their back end
  • Live fleas (however, they are not always easy to see and most live in the environment)
  • Flea allergy reactions - some cats suffer from a severe skin response to flea bites that causes intense itching and irritation of the skin.
  • Flea anaemia - large numbers of fleas feeding on your cat’s blood can cause a dangerous level of blood loss, especially in kittens, old cats and ill cats.
Photo of flea dirt in a cat's fur

Flea dirt in fur

When to contact your vet

If you think your cat has fleas, call your vet practice for advice. They will be able to tell you which flea product to use and how regularly.

Can I have flea treatment without seeing my vet?

Prescription flea treatments are only available if they are prescribed by a vet. If your cat is healthy and visits the vet regularly, your surgery may be happy to dispense a flea treatment without an appointment. Your vet surgery will need to know how much your cat weighs so they can provide the right treatment dose. If your cat hasn't been examined for a while or you’ve tried a flea treatment from a pet shop or supermarket and it hasn’t worked, it might be best to book an appointment.

There are some flea treatments that are available without prescription. Some are categorised as ‘NFA-VPS’ meaning they can only be dispensed by a vet, pharmacist or Suitably Qualified Person and will usually be stored in a locked cupboard. These will tend to be better than products that you can pick from a shelf. If you buy a NFA-VPD product, it’s likely that you will be asked the weight of your pet beforehand.

How to weigh your cat at home

How do cats catch fleas?

Your cat is most likely to have caught fleas from another cat, a dog, the garden, or from your home. People can also transmit fleas to their pets via their clothes and shoes. Fleas can be more common during the summer months, but are seen year round, especially because many of us keep our houses warm throughout the year.

Illustration showing how fleas can live on pets and around the home

Most of a flea problem is in the home, 50 fleas living on your cat = 1000 fleas in the home

How to get rid of fleas

To treat fleas you need to:

Treat all your pets

  • Watch our video on how to apply a spot on flea treatment (below).
  • Treat all of your pets (dogs, cats and rabbits) at the same time.
  • Ideally use a prescription product from your vets. If this isn’t possible, use a NFA-VPS product (from a locked cabinet in a pet shop).
  • Products you can buy of the shelf, without a prescription (e.g. from a supermarket or pet shop) often contain less effective ingredients. If in doubt, ask your vet.
  • WARNING: Never use a dog flea treatment or a household flea spray on a cat. They often contain ‘permethrin’, which is extremely poisonous to cats.
  • Contact your vet immediately if your cat has been exposed to a dog flea treatment or household flea spray.

Treat your house

Treat for worms

  • Fleas can pass a certain type of worm called ‘tapeworms’ to cats.
  • Treat your cat for worms regularly especially if they have had fleas.

Treat any skin problems

  • If your cat has sore, infected or extremely itchy skin, they may need other medical treatment from your vet.

How to apply a spot on treatment for your cat

Will fleas keep coming back?

It can take time to sort a flea problem but once they’re gone it’s easy stop them coming back. Continue to regularly treat your pets and follow our tips below.

Preventing fleas

  • Treat all of your cats, dogs and rabbits for fleas as regularly as your vet recommends (this will depend on the flea product you are using).
  • Check your pets for flea dirt, particularly around their back end and above the base of their tail.
  • Vacuum regularly, especially around your pets' bedding and under furniture.
  • Wash bedding at 60°C or hotter to kill fleas and their eggs.
  • Only allow flea-free cats, dogs and rabbits into your home.

Do flea collars or flea shampoos work?

There are some very effective flea collars available, but it’s important to speak to your vet before purchasing one because there are many on the market that don’t work well at all.

Unfortunately, flea shampoos aren’t often very good at killing fleas.

Can humans catch fleas?

Fleas can bite humans, but can’t live on us. You may notice itchy bite marks around your ankles or on your arms if your cat has fleas. If you see a rash or have a skin irritation which is worrying you, contact your pharmacist, doctor or the NHS for advice.

Published: May 2020

PetWise Pet Health Hub – brought to you thanks to support from players of People’s Postcode Lottery 

Written by vets and vet nurses. This advice is for UK pets only.

Illustrations by Samantha Elmhurst