Flea free naturally

I have three Poodles - a Standard, Miniature and Toy. I treat them with Frontline spray, but it doesn't work for my black Toy Poodle, Abby. As a result I bought a cheaper version from the pet shop yesterday, put it on her and for more than 12 hours she was really demented, running around as if she was trying to get away from something and very distressed. I put it down to the chemicals in the spot-on which I used this time.
It was so upsetting to see her like this and I do not like putting chemicals into her body and wondered if there was an alternative. I have tried cider vinegar in the past. I would try to comb the fleas out but with her black curly coated body this makes it impossible. Also I have well-sprayed my house but these fleas seem to be resistant to anything.
Can anyone suggest a solution as I am at my wit's end.
Judith Stephens, by email