The use of essential oils has become increasingly widespread over the last few years. While wildly popular, scientific support about the positive health effects is limited and contradictory. This is particularly true when discussing health effects on your pet.
Many essential oils, such as eucalyptus oil, tea tree oil, cinnamon, citrus, peppermint, pine and wintergreen are straight up toxic to pets. These are toxic whether they are applied to the skin, used in diffusers or licked up in the case of a spill.
It is important to note that cats and dogs are much more sensitive to scents than their human counterparts. What you may believe to be an insignificant, fragrant scent may be overwhelming and harmful to an animal.