It's a great killer and I put a circle of it around the house on the edge of the house every year to keep away ants, and I know a lot of people that use it directly on their pets.
Problem is, it soaks up skin oils just like it soaks up all the liquid from the insects it kills (honey bees too if used liberally outdoors)--dry, flaky skin anyone?
Also, it's highly irritating if you inhale it or get it in other mucous membranes. So eye and face protection is necessary.