They are also spectacularly successful. Wearing rubber gloves, apply two or three drops of liquid to the skin at the back of the cat's neck, where it cannot lick itself. They can then be combed out with a steel flea comb, along with any remaining eggs and larvae. Some formulas are safe for dogs but not for cats, so be sure to ask your vet for a recommendation. Next, you'll need to treat your whole house.
Fleas spend part of their life cycle snoozing in rugs, under furniture, and in closets.
To eradicate them for good, you must ambush them where they hide. Carpet aerosols are more effective than foggers, as the mist can be directed into every nook and cranny. Vacuum thoroughly afterwards, seal the vacuum bag, and dispose of it. This is a hormone which prevents eggs and larvae from developing into reproducing adults. IGRs don't actually kill adult fleas, so you may want to combine it with an insecticide.