The VET-KEM collar's ingredients are the same as used in their flea spray,
which I use on the ferret bedding.  They seem to have no problems with that
and I have been using it for about a year.  We have 3 cats and seem to be
unable to rid ourselves of fleas as well--last summer was a nightmare (not
just for us at least, the vets here said it was the worst they had seen in
a long time).  By the way, VET-KEM and Zodiac are the same company, their
vet and retail sides respectively, and if you go to a good pet store you
can find the same collar as a Zodiac product.
 
        --Mike, Erica, Ian
        --Buttercup, Fezzik, Alexis, William, Rebecca
        --cats, birds...
[Posted in FML issue 1115]