Quote Originally Posted by Craftlady View Post
Once they are Frontlined it keeps the fleas off their bodies but they can still ingest fleas from other sources.
Yup; frontline will keep fleas from living ON them, but the fleas occasionally may jump on them, maybe leave a little present, and your dog grooms itself and bam, ingested the eggs. Or your dog could be walking around outside and fleas from wildlife have laid eggs, they get it on their feet, get inside ingest the eggs or something, there are so many possibilities. Having them on a monthly flea preventative will certainly help but you can't control the environment. I suggest maybe bombing/spraying your yard to make sure the fleas stay as far away from your pups as possible!