Three years ago I started adding a small splash of distilled white vinegar to my dog, Earl's drinking water when the weather starts to warm up. I had heard somewhere it helps repel fleas. He doesn't seem to notice the vinegar taste. I only add about 1/2 teaspoon to a gallon of filtered well water.
He used to get them every year, and then bring them into the house. I don't use chemicals, especially around my animals, so it was really hard to get rid of them!
Since I've been adding just a little vinegar to his bowl almost every time I fill it, he hasn't had 1 flea! Some days I forget to add it, so if I miss a few days it still seems to work.
I was somehow talked into adopting a beautiful black lab, Gypsy Rose, a year and a half ago, and she has been flea free also!
I found out when she was 8 months old that she was born with Addison Disease, and has to take a pill a day, and get a $100 shot every couple months, but at least - no FLEAS!
This was just taken a few months ago, but the date on the crazy camera keeps going back to 2004 when I change it.