Ivermectin is used for a number of "bugs".  A drop in each ear and a drop
on the base of the tail is good for treatment of ear mites (repeat in two
weeks to catch egg hatch out).  It can be mixed by your vet and given
orally monthly to prevent heartworms (requires weighing your pet each
month to determine correct dosages).
 
You have to be very careful using products containing pyrithins, the most
common "flea killer" used in pet products.  I normally spay my palm with
Frontline and rub it through the ferret's fur.  This is a VERY light
usage of the spray.  Just ONE spritz.  It does immediately make a
difference.
 
We don't, however, use it for flea treatment.  If your ferrets have
fleas, a thorough search of their fur would confirm it.  If you don't
see fleas, don't treat for them.
[Posted in FML issue 5023]