Lots of stuff will kill fleas.
Not much will kill flea eggs.
The key is a treatment regimen - on both the animals and on their entire living space - that'll catch the fleas after they hatch and before they lay a new batch of eggs. Unfortunately...
"The entire life cycle is quite variable, as evidenced by the variability in each life stage progression. As mentioned above, the cycle can be as short as two weeks or as long as two years. That is why it is so important to remain vigilant, even when a flea problem is thought to be under control!" (
Janet Tobiassen Crosby, DVM)
But, you can usually have pretty good success with weekly treatments of the animals with a flea spray or bath and, on the same day, a weekly thorough spraying of the animal's entire outdoor living space with Malathion. If there are eggs in your carpets indoors... weekly insect sprays that smell better than Malathion are available.
- or -
get the stuff from the Vet. Your dogs will collect any fleas that hatch inside and they won't be able to reproduce; problem solved.
Rick