Frontline is safe for ferrets. It is good that you realize that folks do need to check for individual animal types because what is safe for one is not for others. You can find a LOT of very knowledgeable past vet posts on this in these two archives: http://listserv.cuny.edu/archives/ferret-search.html and http://fhl.sonic-weasel.org The first is the FML Archives (which is why the addy seems familiar since you see it in the header of every day's FML) and for searching there for vet replies I suggest that you seek the topic but also seek FML and FHL member vets' names, and on some other searches "from FHL" or look for sukie or sukiec in the from to get some vet posts I've carried over. The second is the FHL Archives, and you can skim what comes out and pull out some of the vets pretty easily from there. BTW, if I recall right you are in a heartworm area, aren't you? In that case make sure that you have flea, tick, and heartworm protection on-board. A number of the past vet posts will help you find the spray info, dose info, application info, false rumor info (and Frontline is a victim of some nasty false rumors), and which critters each given type of med works for and doesn't work for. [Posted in FML issue 4610]