What Is Diatomaceous Earth And How Does It Kill Bugs?

Got roaches? Fleas? Grab the diatomaceous earth! This white powder has no odor, is all-natural, and a must-have because bugs hate it! Find out why.

Diatomaceous earth (sometimes to referred to simply as DE) is one of those handy substances that has all kinds of uses around the home and garden. It is mainly used for pest control, it’s effective at killing everything from fleas and roaches indoors to aphids and slugs outdoors.

What is Diatomaceous Earth?

Pile of diatomaceous powder on a wooden table.

It’s useful, but what the heck is it, exactly? The short answer is fossils! Diatomaceous earth (pronounced “dia-toMAY-shus” earth) is ground fossilized remains of a type of phytoplankton called diatoms, which have existed on earth for millions of years. Of course, to look at diatomaceous earth, it doesn’t look like fossils — it is more of an off-white powder that looks similar to talc and has no odor. In order to see the fossilized diatoms, one must put DE under a microscope. If you are wondering what the fossilized diatoms look like, they generally come in two shapes. The long stick-shaped diatoms are called pennates, and the round, cylindrical diatoms are centric diatoms.

Important: Be sure to use diatomaceous earth marked “food grade.”

How Does Diatomaceous Earth Work?

The reason why DE is recommended for killing bugs is pretty simple. The dust is scratchy, so when critters with exoskeletons (hard shells on the outside) are exposed to diatomaceous earth, it cuts through that protective layer, and the bugs eventually dehydrate and die. That scratchiness, caused by the microscopic edges of the fossilized diatoms, is also why DE irritates the skin and eyes. It is recommended that you wear a mask if you are applying it in large amounts.

How To Use Diatomaceous Earth To Treat Roaches

Courtesy of DiatomaceousEarth.com

Step 1: Give your home a thorough cleaning. Sweep, mop, put away food, and vacuum thoroughly. Maintaining cleanliness is usually the best defense against cockroaches.

Step 2: Dry up any damp areas to prepare for your diatomaceous earth application. Any kind of entrance for a cockroach should be sealed up with caulk.

Step 3: Apply DE anywhere you have seen cockroaches, including around the house along the foundation. Dust lightly, since cockroaches won’t step on diatomaceous earth if the dusting is too heavy. Apply DE anywhere cockroaches can hide, enter your home, and where food is commonly dropped. Don’t apply DE to any area that is consistently damp or wet, since wet diatomaceous earth will not kill insects.

Step 4: Leave DE applied as long as the cockroach infestation continues. Reapply if the DE gets washed away. Once the cockroaches are gone, you can vacuum up the diatomaceous earth but you can also leave it down as a preventative measure against future infestations.

How To Use Diatomaceous Earth To Treat Fleas

Dog - Puppy scratching outside in a flower bed

Diatomaceous earth has been used for years as an insecticide to control fleas.

Step 1: Be sure the areas you are treating are completely dry, and that the room is well ventilated and free of family or pets during the treatment process.

Step 2: Dust the affected areas (pet beds, blankets, surfaces of cat condos, etc.) with the diatomaceous earth using an applicator, or sock filled with the product.

Step 3: Let the DE penetrate the areas for an hour or more (if possible) then vacuum it up. Vacuum daily for maximum flea control.  Treat small areas at a time as you will be vacuuming up the DE and you don’t want to burn out your vacuum’s motor. Shop vacuums work well.

While DE is considered non-toxic to humans and animals; it can be drying to skin, as well as irritate eyes and nasal passages. Please talk to your veterinarian about whether DE is right for treating your pet’s skin and fur.

Using It In the Garden

Diatomaceous earth in the garden

DE is also an effective organic pest control method in the garden for a wide range of garden pests, even those that don’t have hard exoskeletons, like slugs and tomato hornworms. Sprinkle it at the base of plants, or use it to create a barrier they won’t cross.

To protect against beetles you can dust the leaves of any plants that have visible signs of damage.

If it rains, you’ll have to reapply.

Unfortunately, DE will kill all insects with exoskeletons, even the beneficial ones, so be extra cautious when applying and really focus on single plants that show signs of pest damage.

Is DE Safe?

Even though diatomaceous earth is a chemical-free alternative to bug sprays, it is a fine powder and can be irritating for those with asthma or any sort of lung issues. Use caution when applying.

We don’t normally think of fossils as being useful to have around the house, even if they are interesting. In the case of diatomaceous earth, however, a small bag can work wonders on pest problems around the home and in your garden!

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Amber Kanuckel

Amber Kanuckel is a freelance writer from rural Ohio who loves all things outdoors. She specializes in home, garden, environmental, and green living topics.

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Is this a danger for bees? We are afraid to use it because it will kill bees?

Amy Trost

Please, check with your vet before feeding DE to your pet and check with your doctor before taking DE internally. What is good for one pet/person might be bad for another pet/person!

Marni Holmes

DE has also been used on farms for years to keep animals worm-free. It’s put on their food. I used it to treat one of my cats for worms and it works well. But it isn’t always white. The feed stores carry it in bulk and it’s all a light gray. I believe they process it to make it white and it’s for aesthetic purposes. When used correctly, it is fantastic stuff!


Just wondering if it would be good to use on Asian beetles, shake it on them and hope for the best?


Will DE work on spiders and ants?


Will the diat

John C McManus

lI have a nat infestation suddenly. What will get rid of nats?


I do not know about diazinon Earth for gnats. But I often have a nap problem and I control them with homemade gnat traps. Cut a water bottle or 2 liter bottle just below the curvature of the top. Then invert it with the lid off. Put banana peels rotten fruit whatever the gnats seem to be attracted to inside the bottle. If the bottle has no openings where the two pieces meet the gnats should be trapped inside. Then simply throw it away.


I make the same trap, but I find Apple Cider vinegar, a spoon full of sugar and a drop of soap


i have a yardfull of small dogs and a mini pig would this be safe to use in the yard around the pig? for fleas?

Jennifer L Boies

Will it kill bed bugs

june bullied

yes. u can apply it everywhere, light dusting. i was infested 5 years ago and within 2 days i never got bit again and i keep a light dusting in my apt. all the time.


Can I put this in wet cat food and freeze to use later without ruining it?


Why in the world would you put it in cat food of any kind? What are you trying to accomplish by putting it in cat food? At a loss.

Catherine Wood

Please read all the uses of DE…. It is safe ingested! There is a reason it is called “food grade”.


You can use it as a dewormer too.for animals and even people never add to hot foods only cold cool room tempature

Al Toona

Are you referring to the food grade diatomaceous earth, perhaps?

Cynthia Dean

There was a question of how much DE to use for getting rid of fleas on dogs and cats? What is the answer?


Add half cup to large bag of dry food mix shake feed.or a teaspoon in wet food small bowl only like weekly.if even

Laura Hart

FOOD GRADE DIATOMACEOUS EARTH is safe for eliminating bugs in your home and on your pets.
NOT the DE used for pool filters this one is TOXIC to PETS & HUMANS.

Randolph Knackstedt

Look at your local pet feed store. I get food grade DE for $1/pound.


Does this work for bed bugs?

Susan Higgins

Hi Betty, we have read that yes, DE works very well for those nasty bed bugs. Read more here: https://www.diatomaceousearth.com/blogs/learning-center/diatomaceous-earth-natural-bed-bug-control

Erica Crandell

Where do I get food grade DE? Is it safe for you cats to eat if they have tape worms?

Susan Higgins

Hi Erica, yes. Check out this site: Does Diatomaceous Earth Kill Tapeworms. You can also buy it on pet sites like this one: Diatomaceousearth Food Grade Powder.

paula brown

You need to take your cat to the vet if it has tapeworms. Tapeworms as you may know starts out as the larvae of fleas so your cat has fleas first off. Tapeworms can wreck havoc on the health of your cat. The vet will treat that, then you could keep a light dusting o DE on your cat but use food grade as the cat is grooming itself and will get the DE in mouth.

Brian Farmer


What is the difference between food chemical codex grade (food grade) and pool grade DE?

The difference here lies in the way that each type of DE is treated. Pool Grade DE is calcined, meaning that is treated with very high heat. This turns the silicon dioxide that is present in the DE into crystalline silica. Pool Grade diatomaceous earth, and most other calcined DE products, contain high concentrations of crystalline silica. In fact, some can range from 60 – 70% crystalline silica.

Crystalline silica is very dangerous and can be harmful to the health of humans and animals. For this reason, Pool Grade diatomaceous earth should NOT be used for any purpose other than filtration.

Most Food Chemical Codex Grade (Food Grade) diatomaceous earth products, on the other hand, are not calcined and are composed largely of amorphous silica. Food Chemical Codex Grade (Food Grade) DE products contain less than 1% crystalline silica and can be used in animal feed and for insect control. Food Grade diatomaceous earth, such as Red Lake Earth, unlike pool grade DE, is safe to be used around humans and animals.

Susan Higgins

Thank you for this information, Brian!


I was under the impression that you should not use a vacuum for DE. Is that wrong?

Susan Higgins

Hi Lydia, we address this in the story also because DE can can ruin a bag vacuum motor. But the good news, as we mention in the article, is you can use a shop vac if you need to vacuum up a lot of it. But small treated areas shouldn’t be a problem.


I’m sorry, but I did not see that info in THIS article! I did see that you can vacuum the DE up, but nothing about it having to be a Shop vac to get it!!! That being said… Thank you for that info.! That will save a lot of people from having to buy a new vacuum!!! Lol


Oh, I see! Lol… It’s in the comments, not the actual article!!


You actually didn’t see! LOL… It is in the actual article!! Under the section about using it to get rid of fleas. It says that it will burn up your vacuum so use a shop vac. Sorry you didn’t see it!! LOL

Patty Crippen

How much do i us to treat fleas on my cats and dog? I’ve heard about this but wasnt sure how much to us!


Will it also work on spiders ?


Sam Marshall: pool-grade DE is usually treated with another chemical. Not recommended for other uses! You can get a 40-pound bag of “feed grade” DE at your local feed store; it’s the same as “food grade” and will last just short of forever.

Loretta Hoyland

Will this kill squash bugs too? And keep them away too?


You said to get some at Home Depot or Lowes. Can you get this at Menards? Is the name of it DE? and what does the package look like? Very interested. Have this little beetle coming into my house. A dark brown, shaped like a diamond, and has a hard shell. Thanks


I’m pretty sure you can’t get food grade at lowes or menards or any hardware store just be careful and make sure it says food grade anything else can kill you or your pets

Chris Marcellus

Food grade DE is a purer version of DE (very little dirt, etc…). Using non-food grade will not have near the effect food grade will, so yes there is a big difference. Putting food grade DE in your pets food will help with their coat & skin, humans can use it too – I’ve been taking about a teaspoon every morning for the last 4 years (in some water – it has a very slight neutral earthy taste). It has done wonders for my hair & nails (won’t regenerate hair like Rogaine, just help what you already have). As far as an intestinal cleanse, I’ve read one article about it “scrubbing” your intestinal walls, so I use it for the hair/nail/skin benefits. It’s full of silica, which is the beneficial ingredient for humans & pets. Most feed stores will have it.


Been using this for decades and very very inexpensive.. years after it remains after many vacuums.. living in nyc no one would believe me.. as a kid I used to take care of the pool filter and this was one ingredient I had to use


do people use food grade de to cleanse their intestines. I heard they use a
teaspoon with 8 oz water. per day.


Sam Marshall

Great article! What is the difference in” food grade” DE vs. the DE that I use in my pool filter? I am wondering if I can use the pool filter DE for an ant problem that I have outside? Do they work the same way? Thank you.


Best stuff EVER!!!!!

L Petrie

DE is sold in most garden supply stores like D&B Supply out west and Home Depot or Lowes garden centers.


Where can i purchase this for my garden please de

Where is it sold or how do I purchase it
Christie Wight

DE is amazing. Good reminder for garden, tho it will work with both good and bad bugs. Recommended for bedbugs too.

I had a weird even in my apt last winter. Bugs bothering me but not my cat! Resolved the little creeps with DE. Ants will not cross it, put around foundation of house each spring. Washes into soil which gives trace minus to soil too!

I have also taken internally for parasite suspicion. Tough winter! I’m better now 🙂

MaryJane Rissberger

I use it in my cat’s kibble. I put the kibble in a large (gallon) sized canister with 1 tablespoon of the clay, shake the canister to distribute it evenly and then scoop out the daily kibble. My kitty had soft moist stool that are very stinky and this treatment has corrected that issue. The stool is less smelly and slightly firmer. My daughter and I had a kitten that was taking a much larger amount twice daily to treat diarrhea from an intestinal paracite and it helped the kitty recover and now he’s in excellent health.

Susan Higgins

Hi MaryJane, yes, we hear of many people using it that way with great success. We only recommend people check with their vets first. But thank you for sharing your story and we’re glad your pets are doing great!

Ree Enlow

We love DE. Have been using it for years…it works without all the chemical smells, etc since I have allergies and asthma.


Thank you. I was wondering the same thing. I have asthma and Major allergies as well!!!

Also, I was wondering about how much the DE cost? I live in Missouri.

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