How, though, does it control fleas, parasites and insects? It can be sprinkled on the floor (I guess you need a suitable type of floor) and it kills fleas by cutting their external skeleton and desiccating them. As part of the flea’s life cycle the flea spends time on the ground. The flea also jumps on and off the host, which might be our cat. It is when the flea is on the ground that it is killed by diatomaceous earth.
Perhaps the leading point about this product is that it is natural, i.e. no chemicals and it works in a physical rather then chemical manner. The reason why it is made suitable for eating is because it is used to kill insects that migrate to animal feed.
There are considerable number of posts on this subject on the website. If you’d like to read and see more please click on these links, the first for information about food grade diatomaceous earth and the second for information about fleas:
Picture of diatomaceous mining published under creative commons Attribution License – by AlishaV