Bonide's Diatomaceous Earth (100 %, full strength) is a very safe insecticide. It will kill cockroaches, silverfish, millipedes, earwigs, bedbugs, ants, fleas and other crawling insects. Insects may die either by ingestion or contact. Diatomaceous earth is made of sharp and tiny fossilized water plants that cut into the insects' bodies, causing dehydration. Insects that come in contact or ingest Bonide's Diatomaceous Earth will die within two days. It may be applied inside or outside in such places as in homes, food and feed establishments, growing crops, flower gardens, stables, and around livestock. Insects do not develop immunity against diatomaceous earth.