Is diatomaceous earth safe for pets?

What it is

Diatomaceous earth is made of the fossilized skeletons of tiny aquatic organisms called diatoms. Their skeletons are silica, which is mined from old deposits.^[1]

Most diatomaceous earth is amorphous silica, but products can contain very low levels of crystalline silica. 'Food grade' products are purified.^[1]

It was first registered as a pesticide in 1960. Most products are dusts, and some are labeled for pet kennels or for use directly on dogs and cats.^[1]

Thousands of non-pesticide products also contain it, including foods, toothpastes and water filters. FDA lists it as Generally Recognized as Safe, and food-grade products may be used as an anticaking material in animal feed.^[1]

Food grade, pool grade and pesticide grade

Grade matters. EPA warns against using pool-grade or food-grade diatomaceous earth for bed bugs because desiccants made for other uses pose an increased inhalation risk; the pesticide version uses a different size of diatoms, which reduces the hazard.^[5][7]

Heat changes the silica. Calcining diatomaceous earth at high temperature turns part of its amorphous silica into crystalline forms, mainly cristobalite, and NIOSH notes that heating silica-containing materials in kilns can form cristobalite and tridymite.^[11][8]

How much crystalline silica that leaves varies. In a 2025 European Food Safety Authority review of one supplier's feed-grade diatomaceous earth, the natural form held 0.10 to 0.19% cristobalite plus 1.9 to 3.1% quartz, while the flux-calcined form held 4.30 to 5.31% cristobalite. A commercial calcined sample analyzed in a dental-alginate worker's severe silicosis case held 36% cristobalite.^[10][11]

Crystalline silica content isn't the whole story, though. A 2015 lab study of 19 diatomaceous earth samples from around the world found that the crystalline-silica-rich, flux-calcined samples were all unreactive in cell tests, and concluded that crystalline silica content alone is not a sufficient indicator of hazard. The authors note the result still needs testing in living animals.^[12]

Why the dust matters

Amorphous diatomaceous earth is cleared quickly from the lungs and is only linked to mild, reversible lung inflammation.^[1]

Crystalline silica particles are smaller and can build up in lung tissue; long-term inhalation of crystalline silica is linked to silicosis and other lung disease.^[1]

Any dust, including silica, can irritate the eyes.^[1]

NIOSH describes silicosis as a lung disease caused by breathing excessive amounts of respirable crystalline silica; it is not reversible, but it is preventable. NIOSH's guidance is about workplace dust, from jobs such as stonecutting, foundry work and quarry work.^[8]

Not every source is as reassuring as NPIC. A 2019 commentary in the Journal of Insect Science argues that inhaled diatomaceous earth particles can build up in the lungs and lymph nodes, and that repeated use of diatomaceous earth insecticides is linked to silicosis and other lung disease. The same authors note that silicosis typically follows chronic exposure, high crystalline silica content, or work mining these materials, and suggest removing the dust after treatment and limiting direct exposure.^[13]

Feed regulators treat the dust with care too. The European Food Safety Authority panel considered all three forms of diatomaceous earth it reviewed to be eye irritants and respiratory sensitizers for people handling them, and recommended keeping inhalation exposure to a minimum.^[10]

If a pet licks or eats it

Diatomaceous earth works on insects without being eaten, and NPIC says it is not poisonous. When it is eaten, very little is absorbed into the body and the rest is excreted quickly. In one study, people who ate a few grams had no change in the silicon dioxide in their urine.^[1]

Animal feeding studies point the same way. NPIC reports no reproductive or developmental effects in rats fed high doses for six months, and only faster weight gain in rats fed a diet of 5% diatomaceous earth for 90 days.^[1]

EFSA concluded that natural, calcined and flux-calcined diatomaceous earth are safe as a feed additive at 5000 mg/kg of complete feed for all terrestrial animals. Its tolerance studies were done in chickens, piglets and dairy cows, not dogs or cats.^[10]

Some diatomaceous earth dusts also contain another insecticide, like the dinotefuran dust in the prairie dog trial below. If a pet gets into a product, check the label's active ingredients and call your veterinarian or animal poison control with the label in hand.^[14][3][4]

Eyes, skin and coat

Because it is abrasive, diatomaceous earth can irritate the eyes, and on skin it can cause irritation and dryness.^[1]

One registered product carries the signal word CAUTION, says it causes moderate eye irritation, and tells users to avoid breathing the dust and to wear a NIOSH-approved dust mask during prolonged use. Its first aid for eyes is to rinse slowly and gently with water for 15 to 20 minutes.^[6]

Using it around pets

• Read and follow the product label; it limits exposure.^[1][3]
• Move pets, their bedding, toys and bowls out of the area first.^[2]
• Keep pets away until the dust has settled and the area is ventilated.^[2][1]
• Only put it directly on a dog or cat if the product label allows that use.^[1]
• For bed bugs, EPA says not to use pool- or food-grade diatomaceous earth, which can harm you when inhaled; the pesticide version uses a different size of diatoms that reduces the hazard.^[5]
• Apply it lightly. One label says to avoid leaving deposits on exposed surfaces or putting the material into the air in living areas, and to use a bulb or hand duster for cracks and crevices.^[6]
• For fleas, the same label says to treat the floor and bedding in and around pets' sleeping quarters, plus nearby cracks, baseboards and carpeting.^[6]
• Keep the bag or duster in its original container, out of pets' reach, and away from food and water dishes.^[3]
• If dust spills, keep animals out of the area until it is cleaned up.^[3]

Does it work on fleas?

Only in the right spots. Texas A&M AgriLife Extension says diatomaceous earth is unlikely to give practical flea control outdoors, based on its lab evaluations, because it works well only in dry places, and mixing it with water and spraying it seems to stop fleas from picking it up.^[9]

Texas A&M adds that it can be useful against flea larvae when dusted into dry sites such as pet houses and pet bedding.^[9]

In a South Dakota field trial on prairie dog burrows, a dust of 95% diatomaceous earth with 0.25% dinotefuran had no noticeable, consistent effect on fleas, while carbaryl and malathion dusts suppressed them for only one month.^[14]

Diatomaceous earth is one tool, not a whole flea plan; our flea guides below cover treating the pet, the house and the yard.^[9]

Common questions

Is food-grade diatomaceous earth safe to put on my dog or cat?

Food grade means purified, not labeled for use on animals. NPIC says only some registered pesticide products can be used directly on dogs and cats, so use one whose label allows it, and EPA says food- and pool-grade products carry a higher inhalation risk.^[1][7]

What if my dog ate diatomaceous earth?

Very little diatomaceous earth is absorbed when it is eaten. If the product contains another pesticide, or your dog seems unwell, call your veterinarian or animal poison control and have the label with you.^[1][3][4]

How long should pets stay out of a treated room?

Until the dust has settled and the room has been ventilated, or longer if the label says so.^[1][2]

Is pool filter diatomaceous earth the same thing?

No. EPA says pool-grade diatomaceous earth should not be used against bed bugs because it poses an increased inhalation risk. Use a product registered as a pesticide instead.^[5][7]

Sources

1. National Pesticide Information Center, “Diatomaceous Earth General Fact Sheet.” npic.orst.edu/factsheets/degen.html (accessed 2026-10-06)
2. National Pesticide Information Center, “Pesticide Use Around Pets.” npic.orst.edu/health/pets.html (accessed 2026-10-06)
3. U.S. Environmental Protection Agency, “Read the Label First: Protect Your Pets.” www.epa.gov/pets/read-label-first-protect-your-pets (accessed 2026-10-06)
4. ASPCA, “ASPCA Animal Poison Control Center.” www.aspca.org/pet-care/animal-poison-control (accessed 2026-10-06)
5. U.S. Environmental Protection Agency, “Do-it-yourself Bed Bug Control.” www.epa.gov/bedbugs/do-it-yourself-bed-bug-control (accessed 2026-10-06)
6. U.S. EPA Pesticide Product Label System, “Harris Diatomaceous Earth label, EPA Reg. No. 3-18 (EPA-stamped, Apr. 28, 2021).” www3.epa.gov/pesticides/chem_search/ppls/000003-00018-20210428.pdf (accessed 2026-11-10)
7. U.S. Environmental Protection Agency, “Pesticides to Control Bed Bugs.” www.epa.gov/bedbugs/pesticides-control-bed-bugs (accessed 2026-11-10)
8. CDC National Institute for Occupational Safety and Health (NIOSH), “Silica and Worker Health.” www.cdc.gov/niosh/silica/about/index.html (accessed 2026-11-10)
9. Texas A&M AgriLife Extension, Urban Entomology, “Fleas, ENT-3001.” citybugs.tamu.edu/factsheets/biting-stinging/others/ent-3001/ (accessed 2026-11-10)
10. EFSA Panel on Additives and Products or Substances used in Animal Feed, “Safety and efficacy of a feed additive consisting of Kieselguhr (diatomaceous earth) for all animal species (EFSA J 2025;23(4):e9363).” pmc.ncbi.nlm.nih.gov/articles/PMC12000819/ (accessed 2026-11-10)
11. Barbieri et al., “Severe silicosis due to diatomaceous earth in dental alginate: a necropsy study (Med Lav 2020;111(3):222-231).” pubmed.ncbi.nlm.nih.gov/32624564/ (accessed 2026-11-10)
12. Nattrass et al., “The global variability of diatomaceous earth toxicity: a physicochemical and in vitro investigation (J Occup Med Toxicol 2015;10:23).” pubmed.ncbi.nlm.nih.gov/26199640/ (accessed 2026-11-10)
13. Akhoundi et al., “Harmful Effects of Bed Bug-Killing Method of Diatomaceous Earth on Human Health (J Insect Sci 2019;19(5):13).” pmc.ncbi.nlm.nih.gov/articles/PMC6790245/ (accessed 2026-11-10)
14. Eads et al., “Evaluation of Five Pulicides to Suppress Fleas on Black-Tailed Prairie Dogs (Vector Borne Zoonotic Dis 2019;19(6):400-406).” pubmed.ncbi.nlm.nih.gov/30620249/ (accessed 2026-11-10)