We used revolution for our six who had ear mites. They in fact just went back for their revisit to check on the situation and the ear mites are gone. There were no adverse reactions what so ever. I have ferrets ranging in size from just over a pound to four pounds. I was very impressed. I would not do it again personally, not because I don't think its a great product. But because I just can't afford to do six ferrets at a time each month to prevent heartworm and the like. Various ways of treating with ivermectin does the same things for heart worm prevention and ear mites. It won't get the fleas or ticks, but if you are just worried about ear mites, there are cheaper ways to go that are just as if not more effective. If you are trying to kill three or more birds with one stone you may want to consider it. The great news is that there are lots of treatment options out there. Wolfy Please visit: http://www.geocities.com/wolfysluv/ for information on ferret deafness: http://www.geocities.com/wolfysluv/deaf.html [Posted in FML issue 3727]