Diatomaceous Earth (DE) is a fine, white powder made from the fossilized deposits of ancient single-celled diatoms.

Its insecticidal mechanism is purely physical — it does not rely on chemical toxicity.

Under a microscope, the particles of diatomaceous earth have sharp, jagged edges and a porous structure.

When crawling pests such as cockroaches, ants, bed bugs, fleas, or silverfish walk through diatomaceous earth powder, these sharp particles scratch and abrade the waxy protective layer on their cuticle (the epicuticle) — this waxy layer is the pest's critical barrier against water loss from the body.

Once the waxy layer is damaged, the pest gradually dies of dehydration, a process that typically takes 2–7 days.

Diatomaceous earth is relatively effective against the following types of pests: cockroaches and ants (large surface area contact when crawling on the ground), silverfish and booklice (prefer to move along baseboards and in crevices), flea adults and larvae (contact the powder in carpet fibers), bed bugs (effective when crawling through the powder, but cannot reach individuals hidden deep within walls).

Diatomaceous earth is ineffective or poorly effective against: termites (live in mud tubes and do not contact open surfaces), mosquitoes (flying and laying eggs in water), flying stored product pest adults (do not crawl on the ground).

Diatomaceous earth needs to be dry to achieve maximum effectiveness — once dampened, it clumps and loses its abrasive quality, needing to be vacuumed up and reapplied.