Whats the Deal with Tea Tree Oil?

Healing elixir or deadly poison?


Google the words “tea tree oil,” and the results could make your head spin. Some sites sing its praises as a healing elixir with the power to effectively treat bacterial and fungal infections that render your dog’s skin or ears itchy, while others warn that tea tree oil is a highly toxic substance, even applied topically, and can leave your pet paralyzed or even dead. Which view is right?

Both, but keep away from the stuff. There’s too much room for error. Just this year, the Journal of the American Veterinary Association published a report about some 400 cases of tea tree oil toxicity in dogs and cats from 2002 through 2012. In most cases, the oil was applied topically rather than given by mouth, but dogs still ended up with clinical signs ranging from excessive salivation to depression of the central nervous system, lethargy, partial paralysis, lack of coordination, and tremors. Tea tree oil is rapidly absorbed through the skin.

How did tea tree oil become so popular?

Tee tree oil, clear to pale yellow in color with a camphor-like smell (think moth balls), is extracted from the leaves of a tree native to Australia that is similar to the myrtle tree here in the U.S. It is used for skin infections that afflict people but has spilled over into veterinary use and has made its way into many household medicine cabinets. The thing is, in Australia, undiluted tea tree oil is categorized as a toxin so potent that it presents a hazard even during transportation. Packaging there requires child-proof containers and labels with appropriate cautions. That’s not the case in North America. In fact, surveys here have found that the overwhelming majority of Americans who have used tea tree oil were under the impression that it was perfectly safe. Why would they think otherwise? No warning,no worries.

But even a drop or two of the stuff applied to a pet can cause harm; it’s hard to dilute it enough to render it safe for treating skin inflammation and other skin problems, and even if you can, it’s easy enough to make math mistakes with a highly toxic substance. Why take the risk? The smaller the dog, the worse the effects can be. Anecdotally, we found reports that even half a teaspoon’s worth of tea tree oil in a cup of water was enough to cause paralysis in a 25-pound dog. Ingested, tea tree oil is even more hazardous. So even if properly diluted, if the tea tree oil is on a spot that the dog can lick, he can end up taking it in orally and causing himself that much more trouble. (Cats, who are usually smaller than dogs and who lick to groom themselves with much more regularity, definitely shouldn’t be anywhere near tea tree oil, certainly not as a home remedy.)

Commercial preparations

If tea tree oil is so potentially dangerous, even if in minute amounts, why is it sometimes found in commercial products such as dog shampoos? If made by a reputable manufacturer, the tea tree oil is probably properly diluted so that no harm will ensue, says Elizabeth Rozanski, DVM, an emergency and critical care veterinarian at Tufts. But even then, you should talk with your veterinarian about using such a product on your own particular dog. She may or may not have reasons to tell you either that it’s okay or that it’s not a good idea. Even though it’s “natural,” tea tree oil is still a highly potent substance whose use is best supported by a professional opinion.

You’ll want to note that if a veterinary dermatologist ever does prescribe a topical product to control inflammation, itchiness, or an infection in your dog’s skin, chances are it won’t contain tea tree oil. There are other, equally effective chemicals that come without the hazards.

Note, too, that there’s no antidote to tea tree oil poisoning. You can decontaminate a dog’s skin by washing him, but that won’t remove the oil that’s already in his system. And inducing vomiting is not recommended. The thickness of the oil, along with the fact that it can have adverse neurological effects, means induced vomiting can increase the risk for aspiration pneumonia.

Treatment generally falls under the category of supportive care for symptoms rather than decontamination per se: intravenous fluids and medications to try to control any muscle tremors or seizures. Sometimes medications to protect the liver from tea tree oil toxicity are also necessary.


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