Will Dawn Dish Soap Kill Fleas?

  • Written By Dan Edwards on November 10, 2018
    Last Updated: December 10, 2020

There are many home remedies touted for getting rid of fleas. One such remedy is using Dawn, a type of dish soap. There is a lot of misinformation out there about fighting fleas at home. So I’m going to review the facts behind the claims that using Dawn will kill fleas.

We will cover what Dawn is, and some facts about the main ingredients. You will learn whether Dawn really can be used to kill fleas, and if it is effective against flea eggs. Finally, I will detail how to use Dawn for this purpose.


Does Dawn Kill Fleas?

Detergents can be useful insecticides. However, they are most successful on insects that have a soft outer body, such as caterpillars. Fleas possess a tough cuticle covering the whole surface of their bodies. This hard exterior makes them less vulnerable to absorbing poisons.

Fleas are hardy pests – they are, literally, built to stick to your pet. The little combs on their bodies enable them to stay anchored to fur. At this point, you may be wondering how a poison-free dish soap can help.

This is where surfactants come in. As established earlier, surfactants lower the surface tension between water and air. A high surface tension is what allows many insects to walk on the surface of water. Surfactants increase the chances that a flea will sink rather than stay at the surface.

At this stage, it is important to note that fleas are not easy to drown. Fleas will drown if submerged in water for a period of 24 hours or longer. Anything less than that and the flea can revive itself. This recovery can take four to five hours, during which time the flea may appear dead.

The soapy suds that form from Dawn might be capable of asphyxiating a flea. Like many insects, fleas breathe through spiracles. These are openings found throughout the exoskeleton. If any substance blocks these spiracles, the flea can die from a lack of oxygen.

The surfactants in Dawn can also remove a flea’s integumental waxes. This is a natural wax that is found on the exterior of a flea’s body. In insects, this wax stops their bodies from dehydrating. It also makes the flea water-resistant, as the wax repels water. Without this protective layer of wax, a flea is more likely to fatally dehydrate.

Will Dawn Kill Flea Eggs?

Removing living adult fleas is the first step towards a parasite-free pet. Unfortunately, the fleas you can see are just half of the battle. A female flea can lay up to 20 eggs at a time after she has eaten. Females are capable of laying approximately 500 eggs over the course of their lives, meaning infestations can gather momentum quickly if you’re not careful.

flea eggs

The good news is that these eggs are probably not on your pet. They are entirely smooth, so they have no way to attach to fur or skin. Once the female lays the eggs, they will slide off your pet into the surrounding environment. Inside your home, the eggs can be found in your pet’s bedding and anywhere else the animal spends time.

Flea Eggs On Carpet
Flea eggs in the carpet – CC Image courtesy of Denni Schnapp

Depending on the species of flea and conditions, the eggs can hatch in roughly 12 days or so. This means that treating your pet’s environment is just as important as treating your pet itself. If your dog or cat has fleas, anywhere in your home where he or she has been may also have flea eggs.

Dawn can be a useful aid in cleaning affected items, but it shouldn’t be your only tool. The eggs of many insects can survive being submerged in water. Thoroughly vacuum the floors of your home in any room your pet has entered. Make sure you throw away the vacuum bags in a sealed container

Wash your pet’s bedding and soft toys in hot, soapy water. Dawn is as good a product as any to use. As an additional precaution, you can vacuum these items before and after washing them.

Remember that even a few flea eggs left behind can start a new infestation. In my opinion, it is always better to take measures to prevent infestations in the first place. Check with your vet what preventative product is the best fit for your pet.

How to Use Dawn Against Fleas

We have established that Dawn has some effective properties against fleas. Before we get into how to use Dawn against fleas, keep a few things in mind. Soaps like Dawn and others intended for human use have a pH (acidic balance) formulated for our skin. Our furry companions don’t have the same skin pH as we do.

Remember that Dawn is an effective treatment for wildlife soaked in oil. It has powerful abilities to get rid of grease and oils. Our pets have natural oils in their skins that are essential to keep it protected and moist. If these oils are repeatedly stripped away, it can cause irritation in your pet’s skin.

This is why a shampoo specifically formulated for your cat or dog is always a preferable option for regular bathing. It is not recommended to use Dawn or other non-pet soaps and detergents. Dawn can still be of use against fleas without using it on your pet.

At some point before or after administering an anti-flea medication, you will have to use a flea comb. This is a fine-toothed comb that can catch and remove fleas stuck to your companion’s fur. Wiping the dirty comb on a tissue or over a garbage can is not a safe idea as live fleas can easily escape.

flea comb hair

Fill a bucket up with hot water and add Dawn. Make sure the water is thick and sudsy. This bucket will serve as a receptacle for any fleas you find in your pet’s fur. To be sure no fleas will jump out, do not fill the bucket all the way to the top.

Before getting started, use a regular brush on your pet to avoid any painful tangles. Flea combs should not be used on wet fur. Drag the comb from your pet’s head towards the tail, rinsing the comb in the bucket whenever you find a flea.

After you are finished, flush the contents of the bucket down the toilet. Don’t forget that fleas can survive submerged in water for over 12 hours, so don’t dump the bucket in your front yard.

Summary

Using Dawn to kill fleas is not an entirely reliable method. Detergents and soaps that aren’t specifically made for pets can irritate the animal’s skin. There is little scientific evidence that Dawn itself can kill adult fleas or flea eggs. Fleas immersed in soapy water have a higher chance of drowning, but this is not a certainty.

Still, Dawn mixed with water is a good way to rinse off a flea comb and keep fleas trapped. You can also use Dawn dish soap to wash pet bedding contaminated with flea eggs.