Be Careful with Birch and Other Essential Oils in Dogs and Cats

With more and more people using essential oils to enhance their own well being, it is also spreading into veterinary medicine. Unfortunately, most essential oils are toxic to dogs and cats. People who use them for treating or training their pets may, in fact, be unintentionally harming them instead.  

Birch Oil: Birch oil is often used for scent training dogs. Researchers at Michigan State University, College of Veterinary Medicine found that birch oil contains toxic amounts of methyl salicylate. If a dog comes into contact with undiluted birch oil, it can cause severe gastrointestinal ulcers, kidney failure, seizures and death. In addition to this direct poisoning, the smell of birch oil, anise or clove may lead to secondary poisoning from xylitol. Dr. Cheryl Swenson and colleagues found scent trained dogs may confuse the birch oil, anise or clove scent with the wintergreen scent used in many sugar-free products. Most of these products contain xylitol which is safe in people but harmful to dogs and cats.    

Tea Tree (Melaleuca) Oil:  In the last five years, I am seeing an increase in the number of animals poisoned with tea tree oil.  According to the Pet Poison Helpline, “as little as 7 drops of the 100% oil has resulted in severe poisoning.”  The owner brings their dog or cat in for lethargy and problems walking. During the physical examination, I find an oily substance on their skin or in their ears. The animals also have a low body temperature.  They look like a drunk human! In mild cases, the animals will perk up within 24 hours of removing the oil from their skin. Unfortunately, even with supportive care some animals will slip into a coma and die.  
Other Essential Oils: In practice, I have seen dogs and cats with severe skin damage from essential oils. In mild cases, the oil burns the skin causing inflammation. In severe cases, layers of skin slough off causing deep ulcers. The poor animal licks it off causing a secondary burn to their mouth. I saw a cat who sloughed the entire top of her tongue from essential oils. Her owner used undiluted oil as a treatment for ear mites. The insides of her ears were a bloody mess. With intensive care, the cat survived but was deaf for the rest of her life.

-Veterinary toxicology alert: Oils used in ‘scent training’ can harm dogs., DVM360, March 17, 2014.

Published by kristennelsondvm

Dr. Kristen Nelson grew up on a farm in Watertown, Minn., where she developed a deep love for animals of all kinds. She received a Doctor of Veterinary Medicine degree from the University of Minnesota, College of Veterinary Medicine. Kris then completed a small-animal internship at the prestigious Animal Medical Center in New York City. In addition to writing and speaking, she cares for small and exotic animals in Scottsdale, Az. Dr. Nelson is widely quoted in the media. Her credits include Ladies’ Home Journal, USA TODAY, the Los Angeles Times and numerous radio and television interviews. Dr. Nelson has written two books, Coated With Fur: A Vet’s Life and Coated With Fur: A Blind Cat’s Love. Kris and her husband Steve share their home with rescued cats, birds and a dog.

19 replies on “Be Careful with Birch and Other Essential Oils in Dogs and Cats”

    1. At this time, I cannot find any scientific studies to demonstrate the safety of essential oils in dogs and parrots in peer reviewed journals. I would recommend contacting a holistic veterinarian who can give you specific recommendations for your pets. Sorry!

      1. Dear godaddy,
        Have you found peer reviewed research proving toxicity to dogs of many ‘Essential Oils’ used in ways that might be used by a cautious caring dog owner. Has there been sufficient research and ‘Systematic Revues and Meta-analyses’ published in peer reviewed journals? ?

        1. Unfortunately, I have not. There was a retrospective study on tea tree oil toxicity that reviewed 443 cases of toxicity in pets. Here’s the reference if you would like to check it out. Safdar A Khan, et al., ‘Concentrated tea tree oil toxicosis in dogs and cats: 443 cases (2002-2012)’ J. Am Vet Med Assoc Jan. 2014; 244(1):95-99. As you pointed out, we need well designed studies to address efficacy and safety in animals.

    2. My dog has a collapsed trachea and I’ve been using eucalyptus oil in my diffuser for 2 years and no problem with my 4 dogs. I will be careful with my other scents.

  1. A friend of mine, for years, treated her cat’s occasional hair loss with skin eruptions around his ears with a high-quality tea tree oil. He suffered no I’ll effects so I’m wondering if pets having bad reactions to difussed essential oils has more to do with low-quality oils that contain toxic ingredients. offers a free pdf essential oil recipe book with excellent info (such as to never buy essential oils in clear glass bottles, because sunlight degrades oils and the packaging indicates low-quality oil) and sells pure, high-quality oils too.

    1. You are correct that low-quality contaminated oils are the problem. My understanding is that there just isn’t enough of the high-quality oils available to meet the increased demand.

    1. It is hard to answer this question because it all depends upon the dose. I am sure you have heard the saying, the difference between medicine and poison is the dose. Cats seem to be more sensitive to diffused oils than dogs. Birds are the most sensitive because of the air sac system they use to breath.

  2. What about hemp seed oil? I used it for ear mites in kittens ears..they are 8 mo old now and very healthy..this would not be for infusing but just wondered about actual safety..

    1. I cannot find any peer reviewed studies on the safety of hemp oil in kittens. I do know that Dr. Susan Wynn, veterinarian and registered herbalist, states that tea tree oil is toxic in kittens.

    1. It would depend upon the concentration and type of essential oils added to the warmer as well as any health concerns of the pets. I tell my clients to avoid these if anyone in the home, humans or animals, has asthma. Also, some pets are drawn to the warmers. I have seen burns and toxicity after pets chewed on warmers.

  3. Hello Great read. Are you referring to when it’s applied topically? Is diffusing diluted tea tree safe ? Thank you

    1. It would depend upon the dilution. In general, diffused oils aren’t as toxic except for birds and cats. But using them daily may promote allergies. Dr. Richard Palmquist believes that lavender promotes cross sensitization to other antigens in addition to lavender.

  4. My 3 year old dog is doing nose work with birch. She had a tumor develop very fast below her lip. Within days it was beginning to rupture and was removed yesterday. Smear showed mast cells. Biopsy sent in and
    now waiting for results. Could there be any connection with her sniffing birch and mast cells?

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