linda, I had to get a prescription from the vet because Frontline and Advantage don't work anymore. We rarely have fleas, but my big dog is allergic, so even one can cause trouble.
I found the box. It's called Bravecto. A chewable pill given once every 3 months. Worked like a charm. Only gave one dose this spring and haven't needed another so far. Problem is it's expensive. I remember enola had a cheaper alternative, but don't remember the name.
Other than that, all I know is shampoos and sprays, flea collars?, and fanatical vacuuming. Hopefully mutt will know a magic bullet.