The toxic poisons and insecticides in most commercial flea collars will probably kill fleas and ticks. But who knows what else they do to our pets and our environment? PetGuard was concerned that our pets could be inhaling toxic fumes or become severely irritated by the toxic chemicals in these collars. PetGuard believed that many pet owners purchased these collars out of habit rather than consciously making a decision based on concern over the potential dangers to their pets. So PetGuard created an Herbal Collar that we call a scent collar. We make no claims for this collar other than our herbal collar is safe and it 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 a natural blend of aromatic herbs, with a fresh minty fragrance and absolutely no harmful chemicals. Ingredients Oil of Pennyroyal, Oil of Eucalyptus, Oil of Cedarwood, Oil of Citronella, Oil of Rue, Oil of Rosemary.