Regarding FLEAS... MAG, they can apparently live for MONTHS and MONTHS without snacking on anything. Yuck! Nasty little buggers! My daughter used to be allergic to them (probably still is but she's out on her own now) and so a couple of times I HAD to resort to flea bombs. Just know, though, that if you use them you have to redo again (label will explain)in something like 10 days or 2 weeks to kill the eggs that DIDN'T DIE in the first blitz but hatched after it! Advantage is good, but it won't kill off the breeding population that you evidently have, just the ones that get on the cats themselves. Someone once told me that fleas are BORN pregnant; it wouldn't surprise me!