Natural Flea Treatment For Puppies?

My dog had puppies two days ago and we've been battling fleas with her for a while. Now the poor puppies are getting the fleas from their mum :wall: i sat there this morning and picked off as many as i could before having to go to work. So i have a few questions:

1) What flea treatment is safe for a lactating mum?

2) Does anyone have any natural products i can use on the puppies to kill the fleas? Any oils i can dilute with water to spray on them? Anything?

Her last litter we were recomended Frontline spray (bottle says can be used from 2 days old) but i just didnt find it effective. And for $100+ a bottle i dont want to go down that road again when i dotn think it really worked very well last time? People have recommended Advantix to us for our adult dogs but im not sure if it is safe to use on the mum. I had a look on their website and it said nothing about it so ive emailed them but am hoping someone on here may have some solutions for me?