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Diatomaceous Earth for Fleas on Dogs: Safety & How to Use It

Diatomaceous earth can kill fleas on dogs. Although it is considered safe for pets, many vets do not recommend it due to potential side effects. Your dog should not inhale or ingest diatomaceous earth when you sprinkle it on its fur.

Fleas can torment your pet all year round, especially if you live in a region with mild winters.

Although veterinary antiparasitic products are considered the safest and most effective methods to get rid of fleas, they can sometimes cause side effects. For this reason, many dog owners are looking for natural alternatives.

A good substitute for your dog’s fleas is diatomaceous earth. Diatomaceous earth is an effective and inexpensive way to control external parasites. This remedy does not prevent future fleas; it is used to get rid of these nasty pests on the spot.

In this article, you will learn what diatomaceous earth is, if it is safe for dogs, how to use diatomaceous earth on dogs, and more.

What Is Diatomaceous Earth?

Diatomaceous earth is a natural product free of chemicals. It is very effective in fighting many pests, including fleas and ticks. It can also be used along with fertilizer because it is rich in mineral nutrients.

Diatoms are a kind of ancient aquatic algae that fossilized over time. The oldest known fossil diatoms are believed to date from the early Jurassic period (150 to 200 million years ago).[1]

These microscopic shells are mostly made out of mineral silica. Diatoms have accumulated over time in freshwater, oceans, and soil, forming huge deposits of silica.[2]

Diatoms become diatomaceous earth (DE) when they are extracted and ground into powder. This chalk-like powder is microscopically very hard, abrasive, and absorbent, making it useful for many things, including pest control. 

You can use diatomaceous earth to get rid of ants, fleas, ticks, mosquitoes, lice, and other insects.

What Is Diatomaceous Earth

Diatomaceous earth contains a variety[3] of mineral nutrients:

  • Silicon
  • Aluminum
  • Potassium
  • Iron
  • Calcium
  • Phosphorus
  • Lime sulfate
  • Calcium carbonate

What Is the Difference Between Food Grade and Regular Diatomaceous Earth?

Food grade diatomaceous earth has no chemicals, compared to regular DE. The grade of DE you buy should depend on what you intend to use it for.

There are different types of diatomaceous earth, known as grades. There are two grades of diatomaceous earth:

  • Food grade: safe for people and pets.
  • Filter grade: toxic for people and pets.

Food grade DE

Pure diatomaceous earth is organic and safe for ingestion. It can be used in homes with children and pets.

Due to their high silica and mineral content, people often take DE as a dietary supplement.[4]

It can also be used for several other things:

  • Scrub or face mask.
  • Natural cleaning agent.
  • Cereal preservative.
  • Garbage deodorizer.
  • A special ingredient in deodorants and handmade soaps.
  • Insecticide to control external parasites on pets.[5]

Filter grade DE (Garden or Pool Grade)

This type of diatomaceous earth is toxic to mammals because it may contain mixed insecticides and other chemicals.[6]

Filter grade DE is used to filter pool water, produce dynamite, and has other industrial applications.[7]

Food Grade and Regular Diatomaceous Earth

Is It Safe to Use Diatomaceous Earth for Fleas on Pets?

Food grade diatomaceous earth is considered safe to use against fleas on pets. Regular DE (filter grade) is toxic to mammals as it contains chemicals. Always read the label before ingesting or applying diatomaceous earth to your pet.

Diatomaceous earth is considered safe for dogs because:

  • It does not emit vapors.
  • It is not degraded by sunlight or microbes due to its chemical structure.

In other words, it does not have any long-lasting negative effects.

Studies have shown that applying diatomaceous earth to the skin of rabbits five times a week has had no effect on their health.[8]

Feeding DE to rats in high doses for six months also had no effect on their development or reproduction.

Guinea pigs forced to breathe air with diatomaceous earth for two years did not suffer major modifications in their lung tissue.

Only food-grade DE is considered non-toxic for humans and animals, being safe to use:

  • Indoors
  • On plants
  • On pets
  • In adults and around children

Although it is a natural product without chemicals, many veterinarians do not recommend using it on pets due to its potential side effects.

Can Diatomaceous Earth Make Dogs Sick?

Diatomaceous earth can make your pet sick if inhaled or ingested.

Inhalation can cause the following symptoms in pets:

  • Irritation of the nose and airways.
  • Coughing.
  • Breathing difficulties.

Mice forced to breathe DE for one hour a day for a year had a higher incidence of lung cancer.

Diatomaceous earth can cause gastrointestinal upset in pets, such as vomiting and diarrhea, if ingested in large quantities.

DE can also cause skin irritation and dryness, especially in dogs with sensitive skin, so use it with caution.

If it gets into your dog’s eyes, it can cause ocular irritation due to its abrasive nature.

sick dog on vet clinic

Does Diatomaceous Earth Kill Fleas on Dogs?

Yes, diatomaceous earth can kill fleas on dogs. It has been used for decades to kill external parasites. The abrasive edges of the particles pierce their exoskeleton, and its absorbent properties cause external parasites to dehydrate and die.

Fleas and other external parasites are covered with a wax layer. Abrasive DE particles act mechanically on these pests, piercing the wax layer. This disrupts the internal water balance, and the absorbent properties of the diatomaceous earth cause the fleas to dehydrate and die.

Fleas do not develop resistance to DE, as is the case of chemicals.

Diatomaceous earth can only be used to kill fleas. It has no preventive or repellent properties. It acts locally on the skin and does not enter the dog’s body or blood flow (as is the case with veterinary antiparasitic substances).

How Long Does It Take for Diatomaceous Earth to Kill Fleas on Dogs?

Fleas die within four hours of applying diatomaceous earth to your dog. For greater effectiveness, it is recommended to leave it on your pet until the next day (preferably 48 hours).[9]

Apply DE to your dog once a week for 3-4 weeks to make sure you kill all the fleas, both eggs, larvae, and adults.

dog Flea Combs

How to Use Diatomaceous Earth for Fleas on Dogs

You can use food-grade diatomaceous earth for fleas on dogs to powder your dog regularly, or you can combine it with other ingredients.

Regular Diatomaceous Earth for Fleas on Dogs

How to use food grade diatomaceous earth:

  1. Sprinkle diatomaceous earth on your dog’s fur before going for a walk.
  2. Comb your dog’s hair to distribute the powder all over its body.
  3. Avoid your pet’s face. Do not allow your pet to inhale or eat large amounts of DE.
  4. Repeat the process when you return from the walk.

Homemade Diatomaceous Earth Powder for Fleas on Dogs

How to make a powder against fleas with other ingredients:

  1. Add one and a half cups of food-grade diatomaceous earth.
  2. Add one-quarter of a cup of lemongrass powder.
  3. Add one-quarter of a cup of neem leaf powder (Azadirachta indica).
  4. Add 10 drops of lemongrass essential oil.
  5. Mix and shake the ingredients well.
  6. Set the powder aside for 24 hours. 
  7. Use within one year.

How to use homemade diatomaceous earth powder:

  1. Sprinkle the mixture on your dog’s fur, avoiding its face.
  2. Comb your pet’s hair to distribute the powder.
  3. Apply when necessary. 

Other Natural Remedies Against Fleas

If you are looking for other home remedies against fleas on dogs, try these out:


Will Diatomaceous Earth Make My Dog Itch?

Diatomaceous earth can make your dog itch, especially if it has sensitive skin. DE particles are abrasive and can cause minor skin lesions. Diatomaceous earth can also dry out your dog’s skin.

Can Diatomaceous Earth Kill Fleas in Your Home?

Diatomaceous earth can kill the fleas in your home, including their eggs and larvae. Apply DE in places with fleas (on the carpet, bedding, furniture, floors, cracks, etc.) and leave it to act for 48 hours. Vacuum well after 48 hours. Repeat every two weeks until fleas disappear.

About Iulia Mihai (DVM)

Dr. Iulia is a certified veterinarian with more than 10 years of experience in the field. With extensive knowledge of diet, care, and medication, she helps Misfit Animals provide readers with accurate knowledge on technical topics.

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