Diatomaceous earth is also excellent for ridding one’s home of bedbugs. I first heard about it because I had the misfortune of living at a place last year that was infested.
Its used as an anti caking agent in food. I rub it into my dogs hair after giving them a bath to prevent fleas and ticks.
Its completely natural and is a common ingredient in many pesticides. It works especially well on soft bodied critters like snails and slugs.
The only real threat is inhaling it in quantity.