I have used diatomaceous earth succesfully to rid my cat and guinea pigs from fleas. Just rub it in their fur a bit.

The fleas walk over the DE which harms their exterior skeleton and they eventually dehydrate because if it and die.

This works with all animals with an exterior skeleton, like ants, mites, spiders, roaches, etc. So you can use it for many things and don't need to buy chemicals.

I bought a large bucket for 20 euros ex shipping from a chicken supply vendor. It is used in chicken coops againt mites I heard.

You can also buy foodgrade DE. It is said to be good for numerous things like arthritis and such. But also many many more. Just google diatomaceous earth testimonials to learn about them. I personally do not have experience with it in that regard.

But I do believe this is one of those cheap things "they" don't want the people to know about because it is not good for big pharma's pockets.