In response to a question of how Advantage works:
 
Advantage penetrates only the outside layer of skin, where it disperses
over a period of a few hours.  It is not systemically absorbed.  The
active ingredient is specific for the central nervous system of the flea,
and has no effect on mammal cells.  It's so specific, in fact, that it
won't even work on any other type of bug (with the exception of some
types of lice--my associate vet used it on his kids to successfully treat
head lice.  It's completely non-toxic and much easier to use than the
shampoo that MD's prescribe!).
 
Considering the diseases that fleas carry, not to mention anemia from
blood loss in a heavy flea load and the misery fleas cause with itching,
there's not even a remote possibility that the cure is worse than the
disease.
 
I've used Advantage on literally thousands of ferrets; the only reaction
or problem I've ever seen is maybe one ferret out of a hundred has a
slight irritation or redness where it was applied.  It's used safely and
effectively on rabbits, guinea pigs, rats, chinchillas prairie dogs, and
virtually any other mammal you can think of.
 
Deborah Kemmerer DVM
[Posted in FML issue 4149]