Essential Oils for Pets?

There’s promising potential in the field, but there’s still much to learn.

Whiskey is a tough dog. Born in Cairo in 2010, he was taken from his mother when he was 4- or 5-weeks old. He and brothers and sisters were taken to a pet store the size of a supply closet, in a 115-degree heat wave, with no windows or air conditioning. Instead of mother’s milk, he was fed processed cheese and bologna of questionable provenance by the teenaged boys charged with running the store for the absent owner. Immediately after his adoption at about 6-weeks-old, he became seriously ill with a respiratory infection that threatened his tiny, short life. 

But once he pulled through, he relatively experienced any health problems. In Egypt, where garbage is dumped directly on the surface of the street each day for collection, fleas and parasites were a constant hazard, but he was a hardy dog and could handle even the harsh Ukrainian generic pesticide sold in Egyptian pet stores as flea medicine. He lived in Egypt through the 2011 revolution, then moved to Geneva, Switzerland, where winter walks were more like ice skating. 

When he relocated to the Oregon high desert, there was rarely any need for flea prevention. But when visiting with dogs from the warmer, wetter Willamette Valley, a dose was sometimes necessary. For two years, he had tolerated a particular American brand of topical flea treatment without complaint. Then, one day, after he’d picked up fleas from a friend’s dog that had come for a visit, he received his usual dose and began to scratch.

He scratched until his fur, long white hairs, began to fall off in clumps. His pale peach skin turned scarlet, in some places almost the color of blood.  Blisters formed where the medicine had been applied. Washing the medicine off helped the itching a little but the rash spread from the top of his head to the tip of his tail.  He had to be given a course of steroids to calm the reaction. Never again would his owner bring a pesticide-based product anywhere near her newly sensitive terrier.

Essential Oils for Pests and Skin Conditions in Dogs

A 2014 study that reviewed numerous studies of plant-derived products observes, “The use of synthetic pesticides and repellents to target pests of veterinary and medical significance is becoming increasingly problematic.”1 Many animals, like Whiskey, develop sensitivities to these compounds, resulting in allergic reactions, nausea, vomiting and no small amount of desperate worry on the part of pet owners. Immune system response is not the only reason to consider alternatives.  The authors also note “Issues including pest resistance, product residues, withdrawal of active ingredients, undesirable environmental persistence and unacceptable risks to nontarget organisms are among those driving research to identify alternative approaches.” 

Once animals develop an intolerance, or if an owner prefers not to use synthetic products for other reasons, what can a pet owner or veterinarian do to repel pests and treat skin conditions in dogs?

A paper published in the Journal of Medical Mycology in April 2014 on Malassezia Dermatitis, a fungal infection of the skin that causes itching in dogs, reported on the effectiveness of a mixture of essential oils, coconut oil and sweet almond oil.2 The blend of essential oils included lavender, bitter orange, oregano, marjoram, peppermint and Helichrysum italicum (a flower in the daisy family). The animals treated for one month with the blend of oils showed the same clinical improvement as the control group, treated with conventional medication.  Both groups maintained these improvements through follow-up visits 180 days later.

Citronella, lemon and eucalyptus essential oils have been studied as mosquito repellant for topical use.  However, due to the need to frequently reapply, these oils are often supplementary ingredients in commercial insect repellents containing other synthetic compounds.  Citronella, as well as clove and lily of the valley have also been found to be as effective against ticks as DEET.3

In response to the resistance of the mites that cause scabies to topical treatments, Australian researchers studied numerous topical treatments, including herbal products such as tea tree oil and neem. Although neem was not effective, no mites were still alive after three hours of exposure to the tea tree oil product.4 However, pet owners should seek professional veterinary advice applying tea tree oil to your pets, as research published in the Journal of the American Veterinary Association found hundreds of incidents of tea tree oil toxicity in a study of the ASPCA Animal Poison Control Center Database over a period of 10 years.5 Although humans may tolerate 100-percent pure tea tree oil, the same concentration may cause severe symptoms in animals.

In addition to the use of essential oils topically as pest repellent and to treat skin conditions, some vets recommend the use of aromatherapy for animals, tracing its roots back to ancient Egypt and Persia.6 However, aromatherapy may not be appropriate for some animals, such as cats and birds, at least at some concentrations, due to their inability to break down certain compounds. A veterinarian should always be consulted before treating your pets with aromatherapy or any other application of essential oils.

Horses may also benefit from essential oils, applied topically, through massage therapy, or aromatherapy.  One study published in the Journal of Equine Veterinary Science in 2013 found that lavender aromatherapy could reduce the heart rate of stressed horses.7 Researchers exposed two groups of horses to an air horn blast and monitored their heart rate and breathing. One group was then given humidified air with lavender essential oil and one group received only humidified air.  The group exposed to the lavender oil showed a faster recovery from a stressed heart rate.

As the paper's abstract notes:

Following the 15-minute control or aromatherapy treatment, the recovery HRs and RRs were recorded (15 minutes). There were no statistical differences (P > .05) between the control and aromatherapy treatment for resting HR 33.7 ± 3.6 versus 34.0 ± 3.1 beats per minute (bpm), or change to increased HR in response to the air horn. However, the change in HR, after treatment, was significantly greater (P < .02) after aromatherapy (−9.25 ± 3.4 bpm) compared with the control treatment (0.29 ± 1.5 bpm). The RR did not differ (P > .05) between the control or aromatherapy treatment groups for the resting RR or change in RR. These results demonstrate that lavender aromatherapy can significantly decrease HR after an acute stress response and signal a shift from the sympathetic nervous control from the parasympathetic system.

Veterinarian Cassee Terry, of Redmond Veterinary Clinic of Redmond, Oregon, teaches classes each month about essential oils for health and wellness. She says, “I use them on all my animals: bug protection for my horses, tendon strains on horses, skin conditions on dogs and cats. In the clinic, we diffuse oils to reduce anxiety and nausea.”  However, she believes that not all oils are created equal.  “Oils are not FDA-regulated and although it may say ‘100% pure’ it may contain fillers, such as alcohol.”

She notes, “The quality can really make a difference.”

Oils should be tested for pesticide and fillers to ensure purity and should also be tested for potency.  In particular, she observes that “lavender is a known calming, soothing oil.  I use it in all kinds of animals for calming and de-stressing.” 

However, because oils differ in potency and purity, and because different oils vary in their effect on different animals, these considerations, as well as appropriate dosage and dilution, are extremely important.  Dr. Terry says that she makes decisions “on a case-by-case basis.” 

Pet owners: For this reason, it is important to consult a veterinarian knowledgeable about your pet and essential oils before trying them.


  1. George et al., Present and future potential of polant-derived products to control arthropods of veterinary and medical significance, Parasites & Vectors 2014, 7:28, available at
  2. Nardoni et al., Clinical and mycological evaluation of an herbal antifungal formulation in canine Malassezia dermatitis, J. Mycol Med 2014 Sept; 24(3): 234-40. doi: 10.1016/j.mycmed.2014.02.005. Epub 2014 Apr 17.
  3. Thorsell et al., Repelling properties of some plant materials on the tick Ixodes ricinus L. Phytomedicine (2006), 13, 132–134.
  4. Walton, et al. Studies in vitro on the relative efficacy of current acaricides for Sarcoptes scabiei var. hominis, Transactions of the Royal Society of Tropical Medicine and Hygiene (2000), 94, 92-96.
  5. Khan et al. Concentrated tea tree oil toxicosis in dogs and cats: 443 cases (2002–2012), Journal of the American Veterinary Medical Association (2014), 244 (1), 95-99. 
  6. Richard Palmquist, Pet Aromatherapy and Essential Oils: What You Need to Know, The Huffington Post (2011, June 19), available at
  7.  Ferguson et al., Effect of Lavender Aromatherapy on Acute-Stressed Horses, Journal of Equine Veterinary Science (2013, Jan.), 33(1), 67-69. DOI: 10.1016/j.jevs.2012.04.014, available at

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