I can echo the use of DE. When I was a kid our house got infested with a bad case of fleas. My mom dusted all the carpets with the stuff, left it on for 24 hours and vacuumed it up and we never saw a flea again. It works by drying out the fleas and it kills them. Its also very good at getting rid of the eggs which is normally hard to do even with chemical 'bombs"