Diatomaceous Earth kills insects by PHYSICAL action---not chemical. Its fine, fossilized structure scratches the waxy outer coating of fleas and other insects so they dehydrate and die. Because the DE particle is so small--it is not harmful to people and pets. It is a simple mineral---silica. As an added bonus Diatomaceous Earth has a negative charge. This allows it to act as an effective detoxifier since heavy metals, drug residues, and other pollutants, including radioactive ions, have a positive charge. The diatomaceous earth will attract those positively-charged toxic molecules like a magnet and allow them to be removed by the body efficiently through the colon. It also is an effective silica supplement as this important mineral will be absorbed and utilized by the body to support your pet's skin, nail and coat health.