Biospot is definitely a danger for ferrets. I asked my vet about it and her direct quote was: "DO NOT USE Biospot on your ferrets!!! Unlike Frontline and Advantage Biospot is metabolized through the liver and kidneys and can cause damage over time in dogs and cats---think what could happen to a ferret. Advantage and Frontline are truly topicals and not metabolized by organs other than the hair follicles and sebaceous glands of the skin. Much, much safer." Mary and the gang of 15.... Mary McCarty-Houser Pennsylvania Ferret Rescue Association Director, Centre County Branch http://home.sprynet.com/sprynet/ferretlady [Posted in FML issue 2378]