Holistic and Natural Flea Powder for Dogs and Cats. Diatomaceous Earth is made from fossilized microscopic sea organisms called Diatoms with skeletons made of Silica. Silica deposits are mined from bodies of water and are processed in to a powder. Our food grade Diatomaceous Earth is safe to use on pets to help kill fleas. The silica powder breaks the exoskeleton of the flea (and other insects) and causes them to dry out and die. The powder can also be sprinkled on beds and carpet. Leave undisturbed for a few hours and then vacuum. Comes in a reusable shaker.