“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.

When used appropriately, diatomaceous earth can kill off fleas within a few days. What it does is that it punctures the fleas’ waxy exoskeleton using it sharp particles. And once it gets inside, the DE powder sucks all the moisture in their bodies, and consequently, dehydrating them to death.

Since diatomaceous earth is a natural and non-toxic compound, it doesn’t work like most chemical insecticides. The silica particles in diatomaceous earth are sharp and abrasive, and when they come into contact with fleas, they cause tears in the pests’ exoskeletons. Then, the compound absorbs oils from the fleas, drying out and killing them.

Diatomaceous earth is a silky-fine powder made from the fossilized remains of tiny aquatic organisms called diatoms. The sharp edges of the diatoms cut through the hard exoskeletons of fleas, acting as a dessicant or drying agent, effectively killing the fleas and their larvae.

While diatomaceous earth may be seen as an option for those seeking natural flea control, its efficacy is often considered to be limited. Diatomaceous earth is unlikely to kill all adult fleas and does not stop flea reproduction. Fleas left behind are still able to bite pets and reproduce.