Pet Guard Herbal Collar for Dogs is a scented collar, created because of concerns that your pets could be inhaling toxic fumes or become severely irritated by the chemicals in most commercial flea collars. These chemicals and insecticides probably kill fleas and ticks, but who knows what they do to your pet and our environment? Many pet owners purchase these collars out of habit, rather than consciously making a decision based on concern over the potential dangers to their pets.* We make no claims for Pet Guard Herbal Collar for Dogs, other than it is safe and will keep your pet smelling fresh. The herbal oils are impregnated directly into the collar. Whether you choose the collar made for dogs or the collar for cats, be assured that every collar is imbued with a natural blend of aromatic herbs, with a fresh minty fragrance and absolutely no harmful chemicals.