Hello, I'm Dr. Bruce Elsey. I started the All Cat Clinic in Englewood, Colorado in 1978 and Precious Cat Products in 1989. One of the signs that we see at our veterinary clinic are cats with respiratory problems and also kitties with asthma. To answer those problems, we developed respiratory relief litters. This litter is a amorphous silica, which is a very low, dust-free litter. It does not have any perfumes or plant proteins added to it, which can aggravate sensitive upper respiratory epithelium. It's one of those litters that we have found can really help cats and the people that own them with any respiratory difficulties. Thank you.