We are still new at this,and like all new parents worry about every little thing. Fleas in our area are really bad. We put a supplement (for four-legged children) in there food of yeast and garlic.Seems to help.Casey Jones(4 month old male ferret) seems to be doing fine with it. Dose according to weight, but giving Casey a little less. Just wanting to know if this hard on his system? Any info appercited. Thanks,Curtis,Dawn,Casey Jones and brothers and sisters [Posted in FML issue 1721]