It’s always best to prevent a flea infestation from occurring by using preventatives on a consistent basis, but if a treatment for live fleas is needed, you’ll want to know what types of products not only kill the adult fleas, but kill the eggs and larvae, too. Nothing can kill flea pupae but in order to get rid of fleas as quickly as possible, you’ll want to kill the other three life stages of the parasite. If you don’t kill the eggs and larvae in addition to the adult fleas, your cat will continue to get fleas every time the pupae change into adult fleas.  Generally speaking, cats that stay inside are at a lower risk of getting fleas than cats that are permitted to go outside.