There has been much talk recently about cats and essential oils. Are oils safe, or unsafe? What should you believe? The truth is essential oils are indeed a toxic threat to cats. They are rapidly absorbed both orally and through the skin, and are then metabolized in the liver. Cats lack an essential enzyme in their liver, and as such, have difficulty metabolizing and eliminating many essential oils. Cats are also very sensitive to phenols and phenolic compounds, which can be found in some essential oils. The higher the concentration of the essential oil (i.e., 100%), the greater the risk to the cat.