Fleas on cats

cat on white background


Fleas are tiny insects that live on cats, dogs and in your home.

They cause itchy skin, spread disease and can bite humans too. Fleas feed on blood and can cause young, small, old or poorly pets to become very unwell with blood loss (anaemia). Some cats are allergic to flea bites (flea allergic dermatitis).

Think your cat has fleas? You will need to treat all your pets and also your home. Your vet will be able to advise which products to use. It’s easy to prevent fleas by using a veterinary flea product regularly.


Never use a dog flea treatment on a cat

Symptoms of fleas

  • Flea dirt (see picture) – flea poo made from digested blood
  • Scratching and licking
  • Hair loss (alopecia)
  • Spiky fur
  • Enjoying scratches and tickles a lot more than usual because they are so itchy
  • Bites or a rash (on them or yourself)
  • Smelly, infected skin especially around their back end or tummy
  • Live fleas! It’s actually quite unusual to see live fleas unless your pet has a very severe infection.
Photo of flea dirt in a cat's fur

Flea dirt in fur

When to contact your vet

Contact your vet practice for advice if you think your cat may have fleas. Your vet will recommend an appropriate flea product that you should use as regularly.

You know your cat best. If they don’t have the symptoms listed above but you are still concerned it’s always best to contact your vet.

Can I have flea treatment without seeing my vet?

Pop in or give them a call - if your cat is healthy and visits the vet regularly, your surgery may be happy to give you advice and flea treatment without an appointment. If your cat hasn't been seen by a vet for a while or you have tried flea treatments which haven’t worked it is best to book an appointment.

Your vet surgery will need to know how much your cat weighs so they can provide the right medication. For this reason you may need to weigh your cat at home.

How do cats catch fleas?

Cats can pick up fleas or flea eggs from almost anywhere. Even indoor cats can catch fleas. Most commonly from:

  • Other animals, cats and dogs share fleas
  • Outside in the garden or elsewhere
  • The house they live in
  • People bringing them into the home e.g. on shoes.
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

There are a lot of myths and ‘old wives tales’ that give false information about how to treat fleas. Your vet will give you the right advice.

You'll need to:

1. Treat all your pets

2. Treat your house

3. Treat for worms


Treat all your pets

  • Treat all of your pets (dogs, cats and rabbits) regularly.
  • Always use a prescription flea product (from a vet or pharmacy, or from a locked cabinet in a pet shop). They are trialled and tested very rigorously and always have an active ingredient that will kill fleas and/or stop them from breeding.
  • Products you can buy without a prescription (e.g. from a supermarket or pet shop) often contain a weak repellent or a less effective ingredient. They may not work or you may have to apply them very regularly for them to continue to work. This often works out to be very expensive.
  • Your vet will be able to tell you which flea product is most suitable for you and your cat.
  • Your cat might need other veterinary treatment if they have developed bald patches, infections or wounds caused by flea bites.

Treat your house

  • Most of a flea problem is in the house. 50 fleas living on your cat means 1000 fleas in the home. Fleas and their eggs can survive in the house for up to a year. Your vet will be able to recommend a suitable product and when to use it.

Treat for worms

  • Fleas can pass worms to cats. Deworm your cat regularly with a product that covers them against tapeworms, especially if they have had fleas. Your vet will be able to recommend a suitable product.



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.

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 cats, dogs and rabbits regularly

Treat all of your cats, dogs and rabbits as regularly as your vet recommends. Regularly check for flea dirt (as shown above) in your cat's coat, particularly around their back end and above the base of their tail.

Vacuum regularly

Vacuum regularly especially around your pets' bedding and under furniture. Keep your house as clean as possible.

Wash your pets' bedding regularly

Wash bedding at 60°C or hotter to kill fleas and their eggs.

Ensure visiting pets are treated for fleas

Only allow flea-free cats, dogs and rabbits into your home.

Do flea collars or flea shampoos work?

Flea collars should not be used on cats for safety reasons. Flea shampoos are generally not effective and are not advisable because most cats hate getting wet. Speak to your vet for more information.

Can humans catch fleas?

Fleas can bite humans but don't live on us. You may notice itchy little bite marks especially around your ankles or on your arms if your cat has fleas.

See the NHS website for more information on human insect bites.

Photo of flea bites on human skin

Flea bites on skin

Published: November 2018

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