My parents used PROGRAM on their Cocker Spaniel and were not at all impressed with the results. Does this apply to ferrets? I'll leave that up to BIG to decide. [Moderator's note: Don't know what you want me to decide, but since you've uttered "BIG", I'll ham it up a bit. Program does *not* kill fleas! It only keeps them from successfully reproducing. And further, the flea must bite your fuzzy in order for the Program to work. Since fleas can live for months, it may take weeks or months before the results of Program are evident. If you aren't in a situation where you regularly reintroduce fleas into the household then Program can be a very effective solution: eventually the fleas will die off and there will be no new ones to take their place since the Program kept them from reproducing. On the other hand, since Program does nothing to kill existing fleas many people will need more immediate relief. You can use products such as flea sprays to treat your house, call a service like FleaBusters to treat the house, or try one of the newer products such as Advantage or Frontline. These latter two, by all reports, are simply amazing. A single application can nearly instantly disable fleas on your animal before the flea critters even have a chance to bite, and the application lasts for months. Neither is approved for ferrets, but that doesn't mean they won't work for them - they do. The products are similar, though Frontline has the added feature of being waterproof. That may or may not be a plus. BIG] [Posted in FML issue 1667]