No harmful chemicals are used in our Flea Away blend. We combine natural vegetable glycerin, distilled water, and a combination of very gentle and effective essential oils to repel fleas from your home and dog. This can be safely used in areas where your pet lives and sleeps in your home. It can also be used directly on your pet's coat. It can also be applied to a cotton collar or bandanna. As cats metabolize essential oils differently, we do not recommended using this product directly on kitty fur.