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At Blackrock Vets in Dublin we have produced a helpful guide for flea and worm treatments for your pet.

From what age can flea treatment start?

Dogs and cats are usually treated with their first dose around six to eight weeks of age, but for some products to be used there is also a minimum weight. Some treatments can be given earlier if a very young puppy or kitten is heavily infested with fleas. We recommend using prescription-only flea treatments as these products are more effective and safer. Only Veterinary surgeons, by law, can prescribe prescription flea treatments classed as (POM-V) products following a pet health check. 

How long does it take for your pet to be protected?

Once a product is applied, this can work within 24 hours. We recommend using a prescription only flea treatment, dispensed by your veterinary surgeon. Prescription only flea treatments can tackle the whole flea cycle, which includes eggs, larvae and adult fleas. Most over the counter products from pet shops or supermarkets only treat adult fleas and not larvae or eggs and use older, less effective ingredients. 

If your pet already has fleas and you're not using flea treatment as a preventative, you will need to treat your house with a spray. A single flea can lay up to 50 eggs per day; this means that your house will have dormant larvae or eggs ready to hatch and emerge. Treating your pet with a product and treating your house is the most effective method for keeping your pet safe from fleas. Once a pet is treated, prevention is always better than trying to eliminate the infestation. 

How regular are flea treatments required?

This depends on which product is prescribed by your vet; usually, a bespoke plan is made that will best suit you and your pet. Most products are applied every four weeks; this is usually in liquid form and is placed onto the skin at the back of the neck or a tablet. However, there are other product types; we would advise speaking to your vet to create a bespoke plan to suit you and your pet's lifestyle. 

Are certain breeds more at risk of having fleas?

No - fleas do not prefer a specific breed; however, there are various species of fleas that have a target host, such as the dog flea and the cat flea; this does not stop a flea from biting any animal it encounters whether that is a dog or a human 

What are the signs your pet may have fleas?

  • scratching or itching
  • nibbling or biting the skin from the irritation caused by a flea bite
  • black or brown specks in the coat (often mistaken for soil) 
  • live fleas running through the coat – but often only seen in heavily infested animals, fleas can hide very well. 
  • having bites emerge on your own skin
  • miliary dermatitis (cats only) symptoms include scabby skin and fur loss down the spine
  • anaemia (in young animals) from heavily infested puppies or kittens with large blood loss from a flea burden. Young animals can become lethargic and have pale gums

You can use a flea comb to detect any flea dirt or adult fleas in your pet's coat. You can also check if the black or brown speck in the coat is flea dirt by moistening these on paper, if they go red, this is flea dirt. We would be happy to help if you are concerned that your pet has fleas, contact us today. 

Treatment types

There are many products available as well as new products emerging each year. We are here to help with selecting the best-suited protection for you and your pet. We have the most up to date advice and treatments available. We only dispense prescription flea treatments. These are safer and more effective than over the counter treatments and are often combined to tackle other parasites in one medication. 

Only veterinary surgeons can prescribe prescription medications (POM-V) and a vet is required to health assess a pet before prescribing them. For flea and worm treatments, vets usually require a health check every 12 months, which can fall under your pet's annual booster health check. Please note other classes of medications vary with the frequency of health checks required.

Types of flea treatments

We would recommend a bespoke worm/flea treatment plan to fit you and your pet's lifestyle and health status. You can contact us today if you wish to discuss treatments.  

  • Spot ons – these treatments are usually given every four weeks. They need to be applied to the skin by parting the fur on the back of the neck. They can treat fleas, eggs and the flea cycle, but most treatments we recommend combine wormer, flea and tick treatments.
  • Flea tablets – these are tablet forms and are usually given every four weeks.
  • Flea/tick collars – these usually last for eight months and can protect against fleas and ticks. 

We can also demonstrate the application of a spot-on treatment or how to give a tablet during a consultation. You can ask us during your consultation or contact us today to book a nurse appointment. 

Treating the house if a pet already has fleas

When treating an infestation of fleas, the house will need to be treated in addition to your pet receiving medication. A household spray will be recommended; depending on which household product you are using; the following may differ slightly. Read all instructions and warnings on the can carefully before use. 

Please notethese are household treatments and should NEVER be sprayed directly onto a pet.

How to carry out a household treatment

Treating the house for fleas usually involves vacuuming the home fully, including outdoor buildings that a pet has access to (cars included). The vibrations and warmth from a vacuum can also encourage fleas to emerge from hidden areas deep beneath the surface. It is best also to move furniture to ensure you cover the whole floor.

Following vacuuming, all pets (including rodents, birds, fish, reptiles and insects) and people should be removed from the house or treated rooms. Next, the spray is used throughout the house, covering all surfaces on the floor, soft furnishings, and pet bedding.

Spraying a patch test on fabrics is a good idea to carry out before spraying on delicate furnishings. Following this, windows and doors are left open and the house is left for around an hour, longer if possible.

The final stage is to vacuum the house again, discard or clean the hoover collection bag/chamber thoroughly and carry out a thorough vacuum the following day, then twice a week for two weeks. 

Please read the instructions on your product as these may vary in step-by-step guides.

Additional info

Did you know? 

Flea larvae can become infected with tapeworm eggs - If your pet has fleas, you should also make sure they are treated for worms. Therefore, we recommend treating pets with worm and flea treatments. 

Did you know?

Fleas can also pass diseases to your pets. For example, myxomatosis is a serious disease in rabbits that fleas can spread.


Products suitable for one species may not be suitable for another – please ensure you read the label and only apply the product the veterinary surgeon has prescribed for your pet. If you have purchased over the counter treatments, ensure they fit the species you are treating.


There are various worms that can infect your pets, and they can pose a threat to your family. Worms that target pets include roundworms, hookworms, lungworms, and tapeworms, and they are prolific across the United Kingdom. Certain worm can produce more than 100,000 eggs per day, which are then passed in the pet’s faeces and spread throughout their living environment.

Your family can accidentally ingest worm eggs that have been passed through your pet’s faeces. The eggs can then hatch in your intestinal tract, and the worms can travel to various tissues in the body, including the eyes and brain, potentially causing serious infections.

Book a flea and worm treatment appointment with us at Blackrock Vets

Worms are a year-round threat and the only way to keep your pet and family safe is through proactive actions to get the best products. Lungworm, which is passed on by slugs and snails, is potentially fatal and many over the counter products do not tackle this worrying parasite.
Please be aware that many products available elsewhere other than sold at may be ineffective at treating all the species of worms and fleas your pet could get. There are many ranges of worming treatments available including tablets, liquids, granules and spot-ons.