Why Does My Dog Still Have Fleas?

By Dr Eloise Bright 9 Min Read

Fleas are such a problem in warm humid areas, particularly in high density living with lots of animals and free-roaming cats. Yes, we can often blame the cats for this one, but that is a simplistic view and it’s not the whole story.

If we step back and think about them, fleas are fascinating parasites. They are incredibly successful at outsmarting us at every turn. It would be nice to think we could just put a monthly flea product on our pet then forget about it, but this is not always enough, particularly in warm climates. If you are after a more natural approach we will also give a few recommendations of what will and won’t work for your pet.


Most flea products kill adult fleas and stop them laying eggs, but none work instantly. In fact most take around 8-24 hours to kill each flea that jumps on your pet. Unlike many parasites, most fleas live in the environment, not on your pet. And there are always plenty of new fleas waiting in the wings, ready to replace those that are killed.

If you are relying on a flea shampoo, collar or one of those cheap top-spots in the supermarket, you are wasting your time and money too!


  • A small break in flea prevention, even if that was during winter, can lead to big problems later on. Fleas lay 50 eggs each day, so even being a few days late with your flea prevention is all it takes to accumulate a collection of flea eggs.
  • Not all flea eggs hatch at once, they can last for months in the environment. Those flea eggs will will gradually hatch over the following months and come back to haunt you!
  • Stray cats coming into the yard, a visiting flea-infested dog or neighbours cats and dogs can be a source of adult fleas, and those dreaded flea eggs.
  • Sydney has the perfect climate for fleas to survive year-round, so the common practice of stopping flea treatment over winter can lead to problems over summer.
  • Bathing more frequently than weekly can strip top-spot flea products from your pet’s skin and hair. If your pet swims, consider switching to a flavoured chew like NexGard, Bravecto, Comfortis or Panoramis.


  • If you are seeing small numbers of fleas, yet your dog doesn’t seem that worried, continue with your monthly flea treatment all year round and eventually you will start to see fewer fleas.
  • If your dog is incredibly sensitive to fleas and develops hot-spots or has allergies, firstly switch to Comfortis. This monthly flea tablet is the fastest-acting flea product available.
  • An alternative to Comfortis is using Capstar (or a similar product containing nitenpyram) every second day, alongside your regular flea medication. Capstar is perfectly safe to use with any of the other flea and tick products, including our favourites, Bravecto and NexGard.
  • Vacuum the whole house thoroughly, including under beds and furniture. Pay particular attention to areas within a few metres of your pet’s bed.
  • Use a flea bomb for every single room in the house, but make sure you do that good thorough vacuum first to get rid of any particles of dust that might protect the flea larvae from the bomb.
  • The flea bomb will only reach those areas where the mist settles. Under the bed and under furniture may need to be treated separately with a hand-held flea spray like Black Raid or Purple Mortein.


Treatment of the outdoors is more complicated. Ideally all animals surrounding your property should be on flea control, including those stray cats! Warm, dark areas are often flea nests so take a look at the yard and where your pet spends lots of time. Does your dog sleep in the mulch in that shady corner? Does he retreat under the house on hot days?

To tackle fleas outdoors:

  • Sweep up leaves
  • Scare off those stray cats or buy your neighbour some flea prevention for her 20 cats
  • Keep lawns short
  • Limit the use of mulch or fence these areas off
  • Give your pet a cool, flea-proof bed like a trampoline bed to rest on outside
  • Block off the area under the house or down the side of the house
  • If your dog has a kennel, avoid carpet in the base and use an old towel you can machine wash weekly
  • Throw out any old couches or mattresses your pet naps on outside
  • Pool salt can be used as a dessicant or drying agent to kill flea eggs and pupae, but can be irritating to your dog’s skin and is not great for plants. You will ultimately need to block off the area if you can
  • Consider a professional pest company, but all of the above will make any pest spraying even more effective


Make sure any pet beds can be washed in their entirety on a hot cycle in the washing machine (over 60ºC for more than 10 minutes). Do a good wash of anything your dog sleeps on every week. It is not enough to just wash the cover of the bed as the fleas will burrow down into a mattress or foam. Trampoline dog beds are excellent, flea resistant beds for bigger dogs. For smaller dogs, use a nice machine-washable bed.


Sometimes in the hunt for a more ‘natural’ way to protect our pets, all sorts of weird and wonderful recommendations are made on the internet. Some of these are quite frankly very dangerous. At best they can be ineffective and divert your attention from the things that do work. Flea products have years of research into safety and have very strict manufacturing controls and are much safer than all the other whacky advice. Never under any circumstances spray your pet with tea tree oil (which is toxic if ingested), lemon juice (yikes! that would have to sting!), garlic (again, toxic!), apple cider vinegar and citronella (which is used as a deterrent in bark-collars because dogs hate the smell!).

The best natural remedy for fleas is a flea comb, washing bedding on a hot cycle in the washing machine once a week and vacuuming every few days. Then follow the directions above for keeping flea numbers down in your backyard. There is a powder called Flea Busters that is based on boric acid that can be swept into the floorboard gaps or carpets to act as a dessicant for flea eggs and larvae. Just make sure you vacuum it all up before your pets or kids walk on it.


  • Flea medication can seem like it’s not working because nothing kills fleas instantly
  • Treat the environment with flea bombs and regular vacuuming
  • Wash pet beds weekly on a hot cycle
  • Keep lawns short and yards swept
  • If you bathe your pet more than weekly, top-spot flea products may not work

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Dr Eloise is a Clinical Lead at Love That Pet and one of our resident pet care experts. She also curates the select range of vet recommended and approved products which feature on our site.
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