We usually use a Frontline type product on our cats, but I did not give Sasha her dose when I knew she was just days from delivering. I was worried about the kittens being affected by chemical in mama's system. Now they have fleas. We bathed them in Dawn and we change out their bedding frequently. I have not given Sasha her Frontline afraid of hurting babies yet. We need to do something about this. Read to use Borax under bedding, of course not leave it there. Is that the best way to control this, or can I put a Frontline like product on Sasha while she is still nursing the babies?