Fleas on dogs


  • 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 dogs have an allergy to flea bites and suffer severe irritation every time they are bitten.
  • Fleas feed on blood and can cause anaemia in young, old or ill pets.
  • If your dog has fleas, you will need to treat all your pets and your home. Your vet will advise which products to use.
  • Preventing fleas is easy – use a licensed veterinary flea product regularly.
  • WARNING: Some flea treatments for dogs are highly toxic to cats.

How to tell if your dog has fleas

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

  • Scratching
  • Flea dirt (commonly in the fur around the lower back)
  • Bites or a rash (on them or yourself)
  • Bald patches (alopecia) or spikey fur
  • Smelly, infected skin
  • Enjoying scratches and tickles more than usual because they are so itchy
  • Turning quickly or jumping to nibble their back end
  • Live fleas – not always easy to see (most live in the environment)
  • Your dog may become unwell – fleas feed on blood and can cause anaemia (blood loss).
Photograph of little black flea dirts in a white dog's fur

Flea dirt in a dog's fur

When to contact your vet

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

Can I have flea treatment without seeing my vet?

Pop in or give your vet practice a call - if your dog is healthy and visits the vet regularly, your surgery may be happy to give out a flea treatment without an appointment. If your dog hasn't examined 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 dog weighs so they can provide the right treatment dose.

How to weigh your dog at home

How do dogs catch fleas?

Your dog is most likely to have caught fleas from another dog, a cat, the garden, or from your home. People can transmit fleas onto their pets via their clothes and shoes. Dogs are most likely to catch fleas during the summer when fleas are most active.

Illustration showing fleas in the home

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

How to get rid of fleas

There are many myths that give false information about how to treat fleas. To treat fleas effectively you'll need to:

Treat all your pets

  • Treat all of your pets (dogs, cats and rabbits) at the same time.
  • Use a prescription flea product (from a vet or from a locked cabinet in a pet shop). 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.
  • Ask your vet which flea product is most suitable for you and your dog.
  • Your dog may need other medical treatment if they have a flea allergy or have developed skin problems after a flea infestation.

Treat your house

  • 50 fleas on your dog means 1000 fleas in your home.
  • Fleas and their eggs can survive in the house for up to a year.
  • You can buy household flea spray from your vets or online.
  • WARNING: Household flea spray often contains permethrin which is extremely toxic to cats, fish and birds.

Treat for worms

  • Fleas can pass tapeworms to dogs. Deworm your dog regularly with a product that covers them against tapeworms, especially if they have had fleas.

How to apply spot on flea treatment

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

Regularly treat and check

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

Vacuum regularly

Vacuum regularly, especially around your pets' bedding and under furniture.

Wash pet 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 bought without a prescription are not usually very effective. They often only kill the fleas close to them, and by the time the flea has been killed it may have already bitten your pet and laid eggs in your home. There are some effective flea collars available – speak to your vet for more information. Flea shampoos are also often ineffective.

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 dog has fleas.

Published: June 2019

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