We haven't had any ferrets on lasix but we did have one that we had to supplement his potassium. Clyde was on medications for adrenal symptoms and insulanoma and when he went in to have a skin tumor taken off the vet did a blood test and he was found to be low in potassium. So what he told us to do is when he got his gravy to sprinkle a little Nu-Salt (salt substitute) over it and that would help the potassium level. And also that it would not hurt any of the ferrets. They got the gravy once a day as a treat. Here is the link for the Nu-Salt FAQ. http://www.nusalt.com/faq/index.html Barbara S. with Don and all the furkids Sandy, Cindy, Diablo, Mabelene, Charlie Brown, Big John, Wheezy and Suzy Q the kitty. Waiting at the bridge George, Annie, Trixie, Pattie, Mikey, Bonnie and Clyde [Posted in FML 5802]