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.
  • 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 (often on the lower back)
  • Bites or a rash
  • Bald patches (alopecia) or rough spikey fur
  • Wounds and 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 (however, they are not always easy to see and most live in the environment)
  • Flea allergy - some dogs 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 pet’s blood can cause a dangerous level of blood loss, especially in young, old or ill dogs.
Photograph of little black flea dirts in a white dog's fur

Flea dirt in a dog's fur

When to contact your vet

If you think your dog 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 dog 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 dog weighs so they can provide the right treatment dose.

If your dog 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-VPS product, it's likely that you will be asked the weight of your pet beforehand.

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 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 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

To treat fleas you need to:

Treat all your pets

  • Watch our video below on how to apply a spot on flea treatment. 
  • 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.

Treat your house

Treat for worms

Treat any skin problems

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

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, just continue to check and treat your pets and home regularly.

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 dog 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.

What if I can’t get hold of a flea treatment for my dog?

If you are unable to get a prescription flea treatment from your veterinary practice, you may need to consider temporarily using a non-prescription product (from a pet shop, or online). If your dog has a condition that requires prescription flea treatment, it's important to contact your vet to discuss your options.

Published: April 2020

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