I love DE. I especially use it in the areas of the house where the animals sleep.
My nephew came to visit and had lice and the DE even helped to get rid of those where he slept... Of course I did all the other stuff of washing everything in hot water and treating his head but I sprinkled DE in his pillow and no one else got them and they didn't return....
I use Ivermec on my animals and I know there are those that disagree with me but I do like it better than Advantage, or Frontline... If you want to put something on your animal to get rid of fleas, worms, ticks, then Ivermec is great. The downside is it does have to be applied every two weeks... but it costs a lot less and you use very little.... I've not had one animal with an over dose and no issues with pests on my animals...