Last Updated: 07/05/2025
Does your dog have fleas? Even if they have already had treatment? Read more from our vet team on how to get rid of the fleas for good.
Author: Dr Teagan Lever BVSc (Hons)
Reading Time: 52 minutes - long read
Is your dog suddenly super itchy and scratching like there is no tomorrow? Chances are it is probably fleas.
Fleas can cause your pooch to tear themselves apart from scratching, and in the case of those who are allergic it only takes the bite of one to set them off. In some cases flea infestations can result in skin and ear infections from skin inflammation, plus fleas can also transmit flea tapeworm, and in severe cases cause anaemia from chronic blood loss.
The good news is that flea infestations are very treatable if you use the right approach. Before calling the pest exterminators, try out the steps below for a flea free life!
If you're unsure if fleas are the cause of your dog's scratching, read through our guide to How to tell if your dog has fleas.
95% of the flea lifecycle actually occurs off your dog, which means that any adult fleas you are seeing are just the tip of the iceberg. What happens is, adult fleas live on the dog, feeding on blood and laying eggs in the fur. These eggs drop off in areas where your dog sits or sleeps and hatch into a larval stage. The larval stage then burrows down and encases itself in a cocoon to become the pupal stage, which can lie dormant for up to 6 months! Once stimulated by vibrations and movement nearby, the baby flea hatches from the cocoon and jumps onto a nearby dog, cat or unsuspecting human!
When a female flea lays up to 50 eggs a day, it means that one flea can become one million fleas in as little as 6 weeks! This is why year round prevention is so important.
The good news is that with the right preventative on board, no dog needs to put up with fleas, and there are heaps of options to choose from! Depending on where you live and the other preventative products you use, you may want to go with a flea only product or a combined product which covers ticks and/or worms as well.
There's nothing worse than feeling like you've just given your pet a treatment that hasn't helped, but don't be discouraged. Most likely the treatment has been effective, it's just that as quickly as adult fleas are being killed by the treatment, there are pesky new juvenile adult fleas jumping on and hitching a ride. Depending on the product you are using, it can take some time for these fleas to die, so the fleas you are seeing are these juveniles which are on the equivalent of flea death row.
With an effective and long acting flea treatment on board, your dog will work as a flea killing machine destroying all the adult fleas in their path. No new flea eggs will be laid, so over time the levels of flea larvae and pupae in the environment will drop off and there will be less reinfestation. Another reason it pays to be persistent and keep up that treatment year round! If your dog is particularly sensitive to the fleas or there is a heavy infestation in the environment, you can add Capstar, a short acting 24 hour treatment which kills fleas super fast, when you see fleas in the coat for some quick relief.
As well as being persistent, there are some other bases to cover if you are still seeing fleas on your dog:
Weigh your dog to make sure the treatment is the right dose to be effective.
For spot on treatments, be sure to follow any instructions about bathing and water exposure closely as this can reduce effectiveness.
Treat all the pets in the house for fleas. Untreated cats and dogs can harbour egg laying fleas which continue to top up the environmental flea population.
Treat the environment to reduce the number of eggs, larvae and pupae. See below for more details.
In the old days, before we had access to so many new safe and effective spot on and oral worming treatments, pet parents had to rely on flea powders and shampoos. The trouble with these is that as well as sometimes containing some risky chemicals, they are only effective at killing the adult fleas for a very short period of time. This means that although they may reduce the fleas you can see on your pet for a day or two, they don't have a significant effect on the 95% of the flea population which lives off your pet in the environment, and so the problem continues.
There are a range of natural remedies that have been claimed to treat and control fleas, such as garlic, vinegar, salt water and tea tree oil. As well as not being scientifically proven to have any effect, these methods can also harm your pet by causing gastrointestinal upset, or worse- garlic and tea tree oil are toxic to dogs, and vinegar and salt water can be dangerous in large quantities. We strongly advise using a registered and tested product that is specifically formulated to target fleas to ensure both your pet's safety and a quicker path to a flea-free home.
Eggs, larvae and adult fleas will drop off your pet into surrounding areas of the house. If you have an infestation of fleas, you will need to wash their bed, blankets and stuffed toys. Use a hot wash (60 degrees celsius) with regular washing detergent and if possible, place items in the dryer on a hot cycle. Carpets will need to be vacuumed or steam cleaned. The vibrations from vacuuming will help to stimulate the pupae in the environment to hatch so that you can suck up the adults before they get a chance to bite!
You can use flea bombs to kill the parasitic trespassers in your home. Flea bombs are for the environment only and are not to be used to protect humans or animals. Always follow the safety directions carefully on the label when using a flea bomb.
If you have multiple pets in the house, dogs and cats, treat all of them. Treating one of or half your pet population will not be enough. When you give your dog a flea treatment, it treats your dog, not the environment. Untreated pets will be a breeding ground for fleas which will just transfer to the environment causing another infestation.
The fastest-acting flea product available is Capstar, which comes in tablet form and begins to kill fleas on your pet within 30 minutes of administration. It is short-acting, lasting only 24 hours, however its rapid onset makes it useful at helping to clear heavy flea burdens or quickly make very itchy pets more comfortable.
Most modern chews and spot-ons on the market are also quite fast acting, though a little slower than Capstar; the majority will start to kill fleas within 6-12 hours, with most adult fleas on your dog killed within 24 hours.
This will depend on which product you are using (i.e. spot-on vs tablet). Spot-on products are generally applied by parting the hair on the back of the neck, and applying the product directly on to the skin in this area. This location will ensure that your dog isn't able to lick at the area, which would reduce the effectiveness of the product. Oral prevantatives, in tablet or chew form, are given by mouth.
Again, this will depend on which product you're using. Most newer chews and spot-ons on the market will start to kill fleas within 6-12 hours, with most adult fleas on your dog killed within 24 hours. As previously mentioned, Captar tablets will start to kill fleas within 30 minutes. Always check the packaging or manufacturer's website for detailed information on each specific product.
Most flea collars work by gradually releasing a consistent low dose of active ingredients that repel and/or kill fleas. These ingredients diffuse into the lipid (oily/fatty) layer of the skin for full body coverage. Newer flea collars, such as Seresto, tend to be more effective than older brands which may have less reliable modes of action.
There's nothing worse than feeling like you've just given your pet a treatment that hasn't helped, but don't be discouraged. If you have used the product correctly and at the correct dose for your pet's weight, it's most likely that it has been effective, it's just that as quickly as adult fleas are being killed by the treatment, there are pesky new juvenile adult fleas jumping on and hitching a ride.
With an effective and long acting flea treatment on board, your dog will work as a flea killing machine destroying all the adult fleas in their path. No new flea eggs will be laid, so over time the levels of flea larvae and pupae in the environment will drop off and there will be less reinfestation. Another reason it pays to be persistent and keep up that treatment year round!
Every flea preventative will have a labelled usage frequency eg. monthly, three monthly etc. In certain situations it may be okay to use multiple different flea preventatives concurrently, or shorten the interval between applications. However this should only be done under the direct advice of a veterinarian, as some products may be contraindicated for concurrent use particularly if they contain the same or similar active ingredients. Always follow the label directions unless advised otherwise by your vet. You can also contact a Pet Circle veterinarian for advice if needed.
The preventative products on the market have all undergone rigorous testing and have a wide safety margin, and most are still considered safe even if several times the labelled dose is given. If your pet's weight is in between two different weight ranges for a particular product, it is always best to opt for the higher weight range- this won't cause any adverse effects and will also ensure your pet is fully protected, avoiding the risk of under-dosing.
That being said, overdose is possible if a high enough dose is given. Always follow the label's dosage instructions, and if you have any concerns or questions, reach out to your pet's veterinarian or a Pet Circle vet.
Fleas, while a common cause of itching in dogs, are not the only possible culprit. If you have followed all of the steps in this article and your dog is still itchy, there may be an underlying reason for this such as food allergies, atopy or secondary skin infection. For more information on what could be causing your dog's itching once fleas are ruled out, take a look at the following articles:
Why does my dog have sensitive, itchy skin?
Does your dog have food allergies?
When your dog's itchy skin isn't about fleas
It's important to note that due to their route of use and mode of action, oral flea preventatives are not affected by bathing. If you are using a tablet or chew for your dog's flea prevention, there will be no impact on their bathing schedule.
However, if you are using a topical or spot-on treatment for your dog, it is likely that this will have an impact on when you can bathe them. For more information, take a look at How long after flea treatment can I bathe my dog?
Regular shampoos can be helpful in removing fleas and flea dirt physically from the coat, but will only have a temporary effect.
While flea shampoos are available, they are much less effective than modern oral or spot-on treatments, and are only effective at killing adult fleas for a very short period of time- as a result they are generally not needed or recommended.
Flea treatments for dogs may contain dosages or active ingredients that are ineffective or even dangerous for cats. For example, some flea shampoos and spot-ons marketed for dogs that contain pyrethrins can be fatal if used on cats. Any preventative treatment should be used only for the species it is labelled for, unless directly informed otherwise by your pet's treating veterinarian.
Depending on the product, flea and tick prevention can usually be started at around 6-8 weeks of age. Always make sure to check the label, as there is often also a minimum weight that your pup needs to reach before you can safely use the product. Due to the multiple 'all-in-one' products on the market, you can combine flea and tick protection with worming, or you might prefer to give two separate products.
For very young puppies with fleas, or puppies that are too small for preventatives, it is best to ensure mum is on a preventative that is safe to use while lactating (if the puppy is still with mum) and use a flea comb on the puppy to gently remove any fleas. Another option would be Frontline spray which can be used from 2 days of age.
Depending on the product, flea and tick prevention can usually be started at around 6-8 weeks of age. Always make sure to check the label, as there is often also a minimum weight that your pup needs to reach before you can safely use the product. Due to the multiple 'all-in-one' products on the market, you can combine flea and tick protection with worming, or you might prefer to give two separate products.
For very young puppies with fleas, or puppies that are too small for preventatives, it is best to ensure mum is on a preventative that is safe to use while lactating (if the puppy is still with mum) and use a flea comb on the puppy to gently remove any fleas. Another option would be Frontline spray which can be used from 2 days of age.
While most parasite preventatives are generally believed not to cause issues during pregnancy, only some have actually been tested to prove their safety. Therefore, we recommend only using products that have had their safety evaluated during pregnancy and lactation.
For a complete list of products safe for use during pregnancy and lactation, see our Pregnant Dog Guide.
While fleas are an unwelcome guest in any home, following the steps outlined in this article will ensure you're quickly on your way to eliminating them for good. Breaking the flea life cycle by using effective flea treatment, thoroughly cleaning the environment and treating any other pets in the household are key ways to get on top of a flea infestation, while ongoing, year-round flea prevention is crucial to ensure that your pet and home will remain flea-free.
For a more comprehensive guide on the flea treatments currently available, as well as some points to consider when selecting a flea preventative, see our article on Best Flea and Tick Treatments for Pets.
Want to know more? Check out our Discover Page for more tips from our expert vets on keeping your pets happy and healthy.
