This particular side effect (severe shed) has not been reported. I wonder if this may be the result of loss of infected hair shafts (but this would be idle musing only.) However the high margin of safety and the fact that this drug has no apparent significant interaction with other drugs makes it a very viable option for treatment in ferrets. As opposed to more traditional drugs, such as griseofulvin, which has absorption problems, needs daily dosing for up to 6 weeks, and is teratogenic, Program seems like a much more efficient and effective drug for treatment of ringworm in ferrets. With kindest regards, Bruce H. Williams, DVM, DACVP Join the Ferret Health List at http://groups.yahoo.com/group/Ferret-Health-list [This post was followed by an abstract form JAVMA] [Posted in FML issue 3371]