Dear Deb, Our hearts go out to you on your very sad loss. It is hard enough to lose one of our precious ferrets, let alone four at once. Many of our members here in Western Australia have started to use Revolution on our ferrets because, until now, we have had no reliable way to protect our babies against heartworm. Fleas are no problem as Frontline solves that one for us and we are easily able to treat ear mites, but we have had several deaths in some areas due to heartworm infestation and, on veterinary advice, Revolution has begun to be used by many ferret owners in this state. I do not personally use the product, but only because I live in a "heartworm free zone" (if such a thing is possible) and with 38 ferret pets it would cost me around US$165.00 per month to treat them if I felt they were at risk. I have however passed a copy of your story on to "Vanessa" who is about to re-treat her six ferrets in about four days time and, so far, has no ill effects to report; she will endeavour to respond in person very soon. "Rosemary" has about ten days to go before the next monthly treatment is due for her 8 - 10 babies, however, as with Vanessa, there are no ill effects to date. I know they use the pack for largest dogs - teal blue/green marking on pack, but am unsure of doseage recommended by our vet. We will pass this information on shortly. I know this does not help the hurt, but I am really hoping there was another reason why your babies died. I am also hoping very much that the ferrets we have started treating here continue to keep well. Regards to all. Dianne Rohowicz West Australian Ferret & Ferreting Society Inc. [Posted in FML issue 3086]