also helps control fleas and ticks. sold as a filter medium for pools too. cost less than if bought in a feed store or some place like that. I add some to the dirt bath area for my ladies. you could use it to give yer critters (dogs and such) a dry bath"DE causes insects to dry out and die by absorbing the oils and fats from the cuticle of the insect's exoskeleton. Its sharp edges are abrasive, speeding up the process. It remains effective as long as it is kept dry and undisturbed" I don't think it does anything for internal parasites because it only works when dry and as we all know the insides of ours chickens dogs horses etc.. are all moist. it does however work well to keep insects at bay, and if you have an ant problem and it hasn't been raining it does prevent ants from getting in your house if you apply it liberally to the outer parameter if your house and all window seals and other areas they could get in and added protection if you sprinkle it all over your lawn close to your house too, though since it is so good at killing insects it is best to keep it away from flowers so you do not harm our bee friends. it does clump together when it gets wet rendering it inert though. it is make up of old fossilized diatoms from lake beds that are ground up into small particles that cuts up the exoskeleton of insects. it is often added to dust bathes or put on to horses to help keep flies away and various purposes like that.