Can You Use Diatomaceous Earth for Fleas?

By PetMD Editorial. Reviewed by Jennifer Coates, DVM on Jul. 7, 2019

Reviewed for accuracy on July 8, 2019, by Dr. Katie Grzyb, DVM

If you prefer to use DIY products for your four-legged family member, you’ve probably read about diatomaceous earth for fleas. While it does kill fleas, there are some important things to be aware of before using it.

Here is everything you need to know about using diatomaceous earth for fleas so that you can make an informed decision about whether it is the right choice for your home and pets.

What Exactly is Diatomaceous Earth?

Diatoms are single-celled algae that inhabit streams, lakes, oceans and other waterways. Fossilized diatoms, whose cell walls are made of silica, are used to make a fine powder called diatomaceous earth (DE).

The food-grade version of DE contains a much lower level of silica than the versions used for industrial work. It’s labeled “Generally Recognized As Safe (GRAS)” by the U.S. Food & Drug Administration for human consumption.

“Food-grade DE is typically used to sprinkle on vegetable and fruit gardens to help prevent insects from infesting crops. It’s more of a home and garden type situation,” says Dr. Chris Reeder, DVM, DACVD, a board-certified veterinary dermatologist with BluePearl Pet Hospital in Franklin, Tennessee.

How Does Diatomaceous Earth Kill Fleas?

“The small particles of DE actually look like shards of glass when examined under the microscope,” says Dr. Dolores Costantino, a veterinarian with HousePaws Mobile Veterinary Service in Morrisville, Pennsylvania.

A flea that ingests diatomaceous earth will be torn apart, explains Dr. Costantino. But it doesn’t have to only be ingested to be effective.

According to the National Pesticide Information Center (NPIC), “Diatomaceous earth causes insects to dry out and die by absorbing the oils and fats from the cuticle of the insect's exoskeleton. Its sharp edges are abrasive, speeding up the process.”

Is Using Diatomaceous Earth for Fleas Hazardous to Your Health?

Diatomaceous earth can irritate the nose and nasal passages if breathed in, says Glen Ramsey, board-certified entomologist and technical services manager with Atlanta-based Orkin.

And the NPIC warns, “If an extremely large amount is inhaled, people may cough and have shortness of breath. On skin, it can cause irritation and dryness. Diatomaceous earth may also irritate the eyes, due to its abrasive nature. Any dust, including silica, can be irritating to the eyes as well.”

In addition, people who handle diatomaceous earth on a regular basis can develop an incurable, chronic inflammatory lung disease called silicosis, says Dr. Reeder.

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

Veterinarians generally advise against the use of diatomaceous earth for fleas on cats and dogs.

“Do not apply diatomaceous earth directly to your pet. It is not effective for flea control when used in this manner and could potentially result in lung damage if inhaled,” says Dr. Jennifer Coates, a veterinary writer, editor and consultant based in Fort Collins, Colorado.

Aside from possible respiratory risks, “I could see it as being a hazard to the gastrointestinal tract,” explains Dr. Susan Jeffrey, a veterinarian at Truesdell Animal Care Hospital in Madison, Wisconsin.  

“I think the precautions with dogs are similar to those in cats, but since dogs don't groom themselves as often as cats, there may not be as high a risk of adverse gastrointestinal effects,” says Dr. Jeffrey.

Can Diatomaceous Earth Kill Fleas In Your Home?

Diatomaceous earth can and will kill fleas in your home, says Ramsey. The problem, he says, is that homeowners will often misapply or over-apply it.

“If an individual is considering applying a product for pests, it’s always best to contact a pest-management professional. Handling pest issues without a professional can often worsen existing issues,” says Ramsey.

Another thing to keep in mind is that DE only kills adult fleas. And it doesn’t prevent flea reproduction, says Ramsey. “Because of this, flea populations can get out of hand even with the application of diatomaceous earth.”

Your veterinarian is the best person to talk to about any type of flea prevention. “Talk to your veterinarian about the safest and most effective flea preventative for your pets,” says Dr. Coates.

By: Paula Fitzsimmons

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