When it comes to essential oils, a few common misunderstandings about the oils themselves and feline physiology make cats and aromatherapy a deadly mix. The list of oils potentially poisonous to your feline friend is much longer than those that aren't. Most vets and well-trained aromatherapists warn against feline treatment.
The main danger in essential oils is confusion surrounding what they are. Essential oils are aromatic oil steam distilled directly from herbs (or pressed from citrus rinds). They're enormously concentrated. Literally bushels of plant go into making an ounce or so of oil.
Read that again. Now imagine how concentrated poisonous elements become in oils. They must be diluted in vegetable oil or water for use. Undiluted oils can cause chemical burns to liver failure. They're not meant to be swallowed.
A common misperception is since they're "all-natural" and herbal, they're safe and work sort of like magic rather than like drugs -- not so. Aromatherapy is use of essential oils as medicines, cosmetics, hygiene products and emotional stabilizers. It's not -- as a walk through any mall candle or cosmetic aisle might have you believe -- use of perfumes to make you feel good.
Many essential oils contain concentrated cat-killing chemicals. Your kitty's liver is very different than yours, and stuff that's therapeutic to you will build up in her body and cause havoc.
This is a fancy, scientific way of saying "stuff that acts kind of like petrochemicals." All citrus oils, evergreen tree oils and the minty herb bergamot contain them. They're one of the things that make these oils good bug killers (some are even used in professional termite abatement) ... and they can kill your furry lovebug, too.
Phenols are powerful solvents and disinfectants. Stuff that ends in -sol (like Lysol) often contains them. Cats and reptiles find them incompatible with life. They're in oils from the spices cinnamon (sometimes called "cassia") and cloves, the trees birch and melaleuca (a.k.a., tea tree oil), and the herbs savory, thyme and oregano. Sage has a related feline-poisoning chemical.
Salycilates are the active ingredients in aspirin. They're natural compounds found in birch and willow trees, peppermint and wintergreen herbs and their oils, and are toxic to cats.
A Long List of Threats
A whole lot of other herbal essential oils are considered potentially poisonous to cats, though explanations of precisely why are lacking. The list includes tansy and pennyroyal (famous for inducing abortion and liver failure in humans); rue, bitter almond and camphor (potentially poisonous for everyone); mustard, garlic and onions (stinky!); and the more exotic thuja, terebinth, hyssop, mugwort, goosefoot, calamus, sassafras and wormwood.
Safe Aroma Catherapy
There's an answer if you still want to treat your kitty to the benefits of aromatherapy. The watery liquid left over from distilling essential oil is called a hydrosol (they don't contain phenols).
Hydrosols aren't absorbed through the skin and sinuses like oils and are considered perfectly safe for external use on your kitty. If you'd like to use hydrosols, consult a respected herbal and aromatherapy reference for help.
Always check with your veterinarian before changing your pet’s diet, medication, or physical activity routines. This information is not a substitute for a vet’s opinion.
Angela Libal began writing professionally in 2005. She has published several books, specializing in zoology and animal husbandry. Libal holds a degree in behavioral science: animal science from Moorpark College, a Bachelor of Arts from Sarah Lawrence College and is a graduate student in cryptozoology.