Dawn Dish Soap for Fleas

Can You Use Dawn Dish Soap for Fleas?

Witnessing my pets scratching, or even falling ill from flea bites is distressing. So, you’re wondering, can Dawn dish soap (the household detergent) really kill fleas on your dogs or cats?

Certainly! Dawn dish soap can kill fleas on your cats and dogs, but it’s a less effective flea control method compared to IGR sprays. Although it can easily remove grease and oil from wild birds, the flea-killing process is different. 

  • According to Dr. Andrea Miller, Dawn dish soap works by degreasing the fleas’ protective exoskeleton waxy through the surfactant effect, essentially drowning them. Also, the fleas become susceptible to dehydration, and other environmental stressors. 
  • Also, Dawn dish soap reduces the surface tension of water, which means that when you use it to bathe your pet, fleas lose their ability to stay afloat on the water’s surface. This causes them to sink and drown – drowning agent.

Let’s get into the details! 

But first, check these alternative flea shampoos for cats and dogs.  

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How Will Dawn Dish Soap Kill Fleas? 

Dawn dish soap works to clean oil, grime, and grease on wild birds and pets through a chemical reaction called emulsification. 

Does Dawn Dish Soap Kill Flea Eggs

  • Emulsification with Blue Dawn is the result of a chemical reaction between hydrogen peroxide and fatty substances, such as oils from food residue; as explained by a certified veterinarian Dr. Andrea Miller.


The flea-killing process uses a different process than emulsification. Like all dish detergents, Dawn Dish Soap is a surfactant.

  • A surfactant will reduce the surface tension of water and other liquids with which it comes into contact.

Method 1: Reduces surface tension of water – makes fleas sink and drown. 

Typically flea treatments come in the form of topical pesticide solutions such as sprays or powders that need to be used directly on your pet.

  • Dawn dish soap doesn’t kill fleas directly (as pesticides do) – but does so by reducing the surface tension of the water and hence makes the flea sink to its death.
  • The flea’s exoskeletons are made of a protective waxy layer that enables the adult fleas to float on water.

So, dawn (plus other comparable soaps) will reduce surface tension that yields the exoskeleton, and hence the adult fleas will sink and drown.

Dawn dish soap (compared to dog flea shampoo) destroys fleas’ exoskeletons and kills them. But first: How Soap Reduces the Surface Tension Of Water. 

Notably, ordinarily, fleas have a waxy layer, and their small size prevents them from the break the surface tension of water.

But with dish soap, the surfactants will make the fleas sink and drown quickly. The dawn soap makes the pet’s waxy cuticle absorb water and thus drown.

If Dawn Dish Soap is not available, you can substitute any other type of dish detergent, but dish soap is usually more concentrated and will work better.

Method 2: Breaks the Waxy Layer of the Fleas’ Respiratory System

Drowning fleas under normal circumstances is difficult. This is mainly because the respiratory system of fleas has a waxy layer that prevents water from entering.

Further, the wax is also in the trachea and bars water from moving into the respiratory system.

The application of dawn dish soap breaks the wax layer and allows the entry of water into the fleas’ respiratory system.

  • Fleas trigger some skin irritation, anemia (blood loss), or may kill puppies and kittens. But commercial flea treatments can be harsh on kittens’ or puppies’ skin and their young immune system.
  • The most effective method of using the Dawn dish soap will be to give the pets a dish soap + water bath.

Why won’t Dawn Dish Soap help Control Flea Infestations?

Blue Dawn Dish Soap will kill adult fleas, but it does nothing to reduce the risk of flea re-infestation or repel any fleas.

  • Through the drowning process, just a few of the fleas in the house (actually only those on the pets) will be killed by the Blue Dawn Dish Soap
  • Therefore, the fleas that’ll be left running around the surrounding like the yard will jump back and restart the flea re-infestation cycle.

Also, fleas are fast reproducers, so even if you get rid of all the fleas in your house, new ones can easily move in from other parts of the home or yard.

What to do instead: You’ll need an insecticide that’s strong enough to kill both adults and larvae for a serious pest infestation.

Fleas will lay 50 eggs daily, and those eggs will hatch into larvae in a few weeks with most of them being females.


  • Killing adult fleas does nothing to reduce the risk of re-infestation or repel any fleas at all.
  • Soapy water is not enough, you’ll need an insecticide that’s strong enough to kill both adults and larvae for a serious

Dawn dish soap was made to wash dishes and cannot kill or be used as flea treatment, especially for long-term extermination.

Related: Kill Flea Eggs on Cats

Does Dawn Kill Flea Eggs & Larvae?

Dr. Andrea Miller notes that Dawn dish soap is only suitable (in its limited capacity) to kill adult fleas and not kill fleas’ eggs and larvae.

The blue Dawn will mainly drown and kill some of the adult fleas. This will not get rid of all the other 3 flea life stages. They will still be in your house.

Adult female fleas will lay their eggs in the yard or similar surroundings. The eggs will hatch in a few days to give a larval form (lasting a few days) and it develops into a pupa.

The main problem with killing fleas just using dawn or other traditional methods is that you won’t get rid of all the other stages.

  • You’ll need an insecticide with different active ingredients to kill all flea life stages for long-term prevention.


  • If you wash your dogs or cats with blue Dawn dish soap, it won’t cut down the flea population significantly.

Will Blue Dawn Irritate My Pet’s Skin?

Dr. Andrea Miller noted that dish soap is not intended to be used as a dog or cat shampoo (including for flea treatment) due to skin-related issues. For puppies especially, veterinarians recommend only puppy flea shampoo.

  • Frequent skin irritation, a burning sensation, and hair loss are possible side effects of Dawn dish soap if it comes in contact with your dog’s or cat’s skin.

If the pet already has irritation from fleas, and you put Dawn on a part of their skin that is already irritated, it will get worse.

  • Dawn Dish Soap can’t be used as a shampoo for feline or canine pets and should only be used on dishes.
  • Veterinarians recommend using these dog flea shampoo or cat shampoo for your dog and cat respectively. 

When used for routine bathing of your pets, dishwashing soaps will quickly strip your pet’s skin of the natural oils that help to nourish and protect it.

This leaves the skin less well-hydrated and decreases its ability to keep bacterial, yeast, and allergic irritants at bay.

If used on the pet’s skin for routine bathing, Dawn Dish Soap can strip the natural oils off and decreases the ability to fight allergic irritants, yeast, and bacteria.

Natural oils work to protect and nourish the skin. Too much Dawn dish soap can cause the skin to become dry and irritated.

Related: Drain cleaners

So, Should Pet Owners Use Blue Dawn Dish Soap for Fleas Control

Dawn dish soap is not an effective way to remove fleas, but it may be used rarely on severely flea-infested puppies or kittens for fast flea removal.

This is because these puppies or kittens may be too young to use commercial pet products.

  • If you have young puppies or kittens, make sure to use a small amount of Dawn Dish Soap and dilute it with water before using it.
  • Be sure not to leave any Dawn dish soap on the animal for more than 30 minutes at a time because this can change the pH level in their fur.
  • Afterward, use a flea comb to remove any fleas from the animal.

When Dawn dish soap is used on a healthy adult pet without complications and with massive flea infestations, it may be more effective than using water alone to remove fleas.

Dawn dish soap can kill and “exterminate” (removes dead skin and flea dirt) at the same time. It’s only recommended if the pet is exposed to the bugs from locations such as pet daycare or boarding facilities.


Use year-round (prescription) topical and oral flea treatments

  • Effective year-round flea treatment for adult pets typically involves a topical flea medication applied to the animal’s skin.

In the event that you find fleas on a pet in your own home, it is best to purchase over-the-counter Capstar flea killers for emergency use.


Yes, and No, any dish soap will kill fleas – it’ll lower the surface tension (a surfactant) and kill fleas but it isn’t very effective.

If you have any questions please post in the comments section below and I will get back to you as soon as possible.

Thanks for reading!