Hi! I did a lot of research into natural flea fighting and there's a
thread around here somewhere
...I'll see if I can track it down. (found it)
I have to be honest though, we did the natural thing until we ended up with a couple of ticks after one outing, then I went right back to the chemical. It just didn't work out for us between hiking in the woods, going to the beach, and PA just being plain horrible for fleas and ticks.
Depending on how much time you spend outdoors though and what your area is like, there is a lot of good info out there.
(One thing I still do, if they have gotten in your house, sprinkle 22 mule team borax everywhere. Some say to wet it a bit after, others don't. Wait a couple of hours and vacuum. You want to have everyone out of the house while your doing this as it is an irritant.)
Good luck!