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Does Diatomaceous Earth Kill Fleas? Vet-Approved Facts & FAQs

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By Nicole Cosgrove

Food-Grade Diatomaceous Earth

Vet approved

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Reviewed & Fact-Checked By

Dr. Lorna Whittemore

MRCVS (Veterinarian)

The information is current and up-to-date in accordance with the latest veterinarian research.

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As pet owners, we know that fleas are usually a part of the deal. The uninvited guests catch a ride with our pets and end up in our home, linen, carpets, and anywhere else they please. It’s our responsibility to keep our pets safe from these pesky critters.

If you are looking for an effective and non-toxic flea-busting solution, diatomaceous earth (DE) may be a good product for your pets, home and yard. The name is a mouthful, but so are its benefits. There are many diatomaceous earth products available for many uses. However, only food-grade diatomaceous earth is recommended for direct application to your pets.

What is Diatomaceous Earth?

Diatomaceous Earth is a type of fine powder made from fossilized algae, known as diatoms, found in oceans, lakes, and other waterways. These deposits are found all over the world and have been used for many years. The ancient Greeks used diatomaceous earth to make building materials, and today it is used for various applications.

The cell walls of the diatoms are made of 80%–90% silica, but food-grade DE has a lower level of silica than the type used in industry and is safe for human consumption. It is also used in vegetable gardens to help prevent insects and pests from infesting the crops.

Diatomaceous earth also has industrial uses.1 It is a filler and can prevent lumps from forming in medicines, plastics, pet litter, and food. Its abrasive qualities make it useful for scrubbing, and because it’s a desiccant in nature, it can be used to clean up spills. DE is used as an insecticide in chemical testing and to remove unwanted material from drinking water.

Does Diatomaceous Earth Work Effectively to Kill Fleas?

flea allergy dermatitis on dog
Image Credit: February_Love, Shutterstock

DE can look like shards of glass when examined under a microscope. The edges of the diatoms are sharp and can cut through the hard exoskeleton of fleas causing micro wounds. It is a powerful desiccant and dries them out by absorbing the fats and oils from the cuticle of the flea’s exoskeleton, and the sharp edges are abrasive and speed up the process. This effectively kills the fleas by abrasive action and dehydrating them.

Adult Fleas

Diatomaceous earth is considered a mechanical killer instead of a chemical killer, making it an effective, natural, and non-toxic solution for killing adult fleas. However, while food-grade DE is effective for killing fleas, flea populations can still get out of control, so it’s not the most effective method of prevention or control because DE is only effective in killing adult fleas, and it doesn’t prevent reproduction. Therefore the eggs and larval stages will continue to perpetuate the infestation. All life stages must be targeted to effectively get rid of an infestation of fleas.

Limited Effectiveness

This also means that it is not the best method for pets allergic to flea saliva because of the rate at which it kills fleas. A product that kills fleas quickly will reduce the flea population quicker, which reduces the time pets are exposed to flea saliva. Some pet owners will swear by the effectiveness of DE, but because of its limited effectiveness, pest control experts use stronger formulas.

Is Diatomaceous Earth Safe?

Diatomaceous earth
Image Credit: Mona Makela, Shutterstock

While there is not enough reliable information about the safety of diatomaceous earth, people who work with the product have experienced some side effects. Some forms of DE may be harmful to the lungs if inhaled, especially to people with respiratory problems. When it gets on the skin, it can cause dryness and irritation, and its abrasive qualities can irritate the eyes.

It’s important to remember that our pets are no less vulnerable to these side effects. Pets groom themselves, more so cats than dogs, which may put them at risk for gastrointestinal effects. Many vets generally advise against the use of diatomaceous earth for pets.

How To Use Diatomaceous Earth

There are a few ways you can use diatomaceous earth to kill adult fleas

On Your Pet

Food grade DE is a safe method to kill fleas by applying it directly and rubbing it into your pet’s coat. However, it needs to be used with caution. DE is a drying agent, so it may cause issues for animals with respiratory problems. This also applies to pet owners, so it is recommended to wear a mask when applying it.

It is also best not to apply directly on your pet if it is experiencing dry or irritated skin. It is important to keep it away from your pet’s face, and after a full day, you can gently shampoo your pet to get rid of the dead fleas and prevent drying out the skin.

In the House

Using DE in the environment is the best and safest way to use it. It can be sprinkled and spread in the areas where your pet sleeps or where it comes in and out of the house. First, you will need to vacuum your carpets thoroughly. You can then apply the DE to your surfaces using a sieve to evenly spread it around without forgetting the corners.

You can leave the DE on the surfaces for up to two weeks before vacuuming it. It is then recommended to remove fleas from your pet at this time. While removing all of them is impossible, the DE sprinkled around the house will assist. Every time your pet comes into contact with the DE, it will kill what’s been left behind on its coat.

In the Yard

Diatomaceous earth
Image Credit: FotoHelin, Shutterstock

Diatomaceous earth can be very effective and safe in the yard. However, you will need a larger quantity. The climate and weather conditions will also determine its effectiveness, as it doesn’t work when wet. If you live in a humid climate, you will need to reapply it more often.

How Can You Keep Your Pets Safe From Fleas?

As a pet owner, you understand how susceptible dogs and cats are to fleas; however, our furry friends can be protected. Follow these tips to prevent and keep your pet safe from fleas:

  • Brush your pets regularly while checking for fleas.
  • Prevention is vital; use preventative treatments recommended by your vet.
  • Don’t wait until you see your pet scratching before checking for fleas.
  • Check your pet for fleas after a walk in a wooded area or area with long grass.
  • Regularly vacuum your home.
  • Wash your pet’s bedding and your rugs regularly.
  • Keep your grass mowed and short.
  • Remember to treat the environment as well as all pets at the same time.


Food-grade diatomaceous earth can kill fleas because of its abrasive and desiccant qualities. It is also a safe and non-toxic alternative for our pets. However, it must be used cautiously, and there are more effective flea control and prevention methods. Fleas don’t need to be a constant hassle in your home, nor do you have to resort to harsh chemicals. DE can kill fleas on our pets and in our environment if it is used correctly and with caution.

Featured Image Credit: Anna Hoychuk, Shutterstock

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