A friend told us about a method is very effective. 1 gallon of water, add 4 to 6 teasoons of white vinegar to it, and give it to your pets as their only drinking water. We havn't seen a flea in over ten years. It works on any animal. We have a dog (7yo) that has never seen a flea. Commercial flea preparations are bad for the health of our pets AND US!! I am going to try this. I imagine it sours the blood? We will see! I hate Chemical treatments!!!