With 6 dogs and 5 cats, fleas (and ticks) have always been a concern. Vet has given Advantage or Revolution and both work but yes, both expensive. I've recently heard about, and will try this spring, Brewer's Yeast. Sprinkle some on the food and although humans or furkids can't smell anything, I understand that something in it gets in the system and will definately repel fleas and ticks. Supposedly it works with humans keeping mosquitoes away. THAT I figure is worth a try for me too. Certainly can't hurt