It's flies, not fleas!! I know that Brewer's yeast and garlic are supposed to help prevent fleas; not sure about fliews. We live by the ocean, and in the summer, the green flies can bite mercilessly, even our dogs. My Lab Star is not so much the target as our longer haired Cody, a Husky/Shep. This summer she got two wicked bites on her ears that took weeks to heal! Thanks to everyone who offered suggestions. Hope your Labbie friend gets some relief!!