Diatomaceous earth is non-toxic to pets and humans, but it kills insects by destroying their exoskeletons. The roaches will take the “bait” back to their nest and feed it to the other roaches, who will also die.

How long does it take for diatomaceous earth to kill roach?

How long will it take diatomaceous earth to work? Diatomaceous earth isn't an instant solution but you should start to see results within two weeks. DE doesn't kill insects on contact so they might not die until they've returned to their nest. You might not see the dead roaches but you should notice fewer living ones.

How do you use diatomaceous earth to kill roaches?

Apply DE anywhere cockroaches can hide, enter your home, and where food is commonly dropped. Don't apply the DE to any area that is consistently damp or wet, since wet diatomaceous earth will not kill insects. Use an applicator such as the JT Eaton Duster to spray behind switch and outlet faceplates.