Introduction
Several years ago, I wrote a blog to dispel the concern that it is not safe to diffuse essential oils around cats. I did -and still- err on the cautious side by recommending that it is not a good idea to apply essential oils topically, to never allow your cat to ingest essential oils, and when diffusing essential oils around cats to ensure the room is well ventilated.
I was and still am concerned at the fearmongering and misinformation that exists regarding the use of essential oil around cats.
Why is it that there is still so much misinformation regarding the safe use of essential oils around cats?
I typed ‘essential oils, safety and cats’ into Google and more than 9.87 million results were listed.
I have had cats and dogs all of my life, and have worked with essential oils for most of my life. I certainly do not want to expose my furry loved ones to any hazardous substances.
Are essential oils hazardous to cats?
I decided to check out several websites for common cat hazards, focusing on websites belonging to veterinary medicine schools.
One website listed many common indoor plants which can your cat extremely ill and potentially be fatal such as poinsettias, lilies, holly, tulips, baby’s breath and hydrangeas - just to name a few.
It goes without saying that pesticides and garden products such as fertilizers, weed killers and snail bait; along with other products such as ethylene glycol antifreeze, paint thinner, swimming pool chemicals; and many household cleaners such as bleach, detergents and disinfectants; are also very hazardous for your cat.
However, interestingly essential oils were not on this one list.1
Another veterinary medicine website suggests that pet owners should use essential oils with caution around their pets. This veterinary medicine school website was more concerned with the respiratory irritation that may be caused when the cat inhales an essential oil.2
Symptoms of respiratory irritation include watery nose and eyes, drooling, vomiting, and difficulty breathing. Difficulty breathing can easily be distinguished from expelling a furball as the cat crouches low to the ground with little abdominal movement and no furball production.2
This website also mentioned that cats may tip the diffuser over, hence the possibility that the cat might ingest the spilled oils. The author of this blog correctly explains that by diffusing the oil, you release micro-droplets into the air which may collect on the fur of your cat, and when the cat grooms itself it will ingest these essential oils.2
This all leads to the point that you should not diffuse essential oils in an enclosed space around pets, especially when you to not allow your cat the option to vacate the area in which the diffuser is placed.
Now, on this same website I was surprised with the extensive list of essential oils that are considered toxic to pets: basil, bergamot, bitter almond, cinnamon, clove leaf, eucalyptus, geranium, juniper, lavender, lemon, lemongrass, lime, mint, myrrh, orange, pine, rose, rosemary, sandalwood, sassafras, tarragon, tea tree, wormwood and ylang ylang.2
There are some essential oils on this list that I consider very hazardous even for humans, such as bitter almond, sassafras, and wormwood.
At this point, I also decided to check some of the books that have recently been published regarding using essential oils on cats.
Miranda Ross - who purports to have written an authoritative guide to using essential oils on cats - suggests some of the essential oils that should be avoided by cats include spearmint, eucalyptus and rosemary; while some extremely safe oils for the cat include geranium and lavender.4
This book written by Miranda Ross, who is also an expert at making bath bombs and growing orchids, provides no references regarding the list of oils that are safe or not safe to use with cats.
On the other hand, Emily MacLeod, author of Essential oils for Cats, lists “geranium (high in phenols)” as “not advisable” to be used with cats, but then states that spearmint, rosemary, peppermint lavender, ylang ylang, and blue gum eucalyptus as being acceptable to use with cats.3
By the way, geranium has no phenols.
I was also surprised at the dilutions that MacLeod recommended for topically application.
She is correct to say essential oils must be highly diluted if its going to be used for cats; however, she then goes ahead and recommends a ratio should be fifty parts carrier oil to 1 part of the essential oils.3
Do your sums – this is a 2% dilution. This is what I would consider suitable for humans; however, this is way too high for cats, more importantly with what we do know the regarding the risks about using essential oils on cats, I certainly would not be recommending topical applications for cats.
Confused? I am. Who can you believe?
Another website suggested that ‘hot oils’ rich in phenols such as cinnamon, eucalyptus, oregano, thyme, basil, tea tree, wintergreen, citronella, ylang ylang and clove bud are a no-no, as they can cause liver damage if ingested in significant quantities.5
Firstly, sorry for being picky, but there are several oils (eucalyptus, tea tree, wintergreen, citronella & ylang ylang) in this list that do not even contain phenols, and notice the language being used: ‘if ingested in significant amounts.’
Exactly - cats should not be allowed to ingest any essential oils, and this also means being extremely cautious when topically applying essential oils onto your cat as they are likely to lick the topically applied oils, hence accidently ingest the oils.
Even the ABC has got on the bandwagon, repeating the same old list of ‘not to use essential oils’ without any fact checks. However, the author of the ABC blog did have a point that with active diffusion - that is, using an ultrasonic diffuser - it is likely that the mist may land on furniture, bedding or on your pet’s coat and be ingested while grooming. Once again, the main concern is not the direct inhalation, but the accidental ingestion.6
By the way, birds are very different – it is best to avoid the use of essential oils around them altogether.6
The ABC article also explains that pets with existing respiratory conditions, such as asthma or bronchitis, are at greater risk of developing respiratory distress. The author of the blog cites Chief Veterinary Officer, Dr Hoolahan, who states the Animal Poisons Helpline has received several calls regarding small dogs and cats that have become lethargic and unsteady on their feet after being in enclosed spaces with diffusers for prolong periods of time.6
I will come back to this, but toxicity is very much dose dependent and I am adamant that the dosage of essential oil that may be inhaled through diffusion is extremely small and unlikely to be toxic.
Now, let’s go to someone who knows what they are talking about when it comes to essential oils. That is, Robert Tisserand: for whom I have a great deal of respect and admiration.
It looks like Tisserand has also recently updated his blog regarding cats and essential oil safety.
These long lists of essential oils that are either ‘safe’ or ‘toxic’ to cats do not make much sense at all. As Robert Tisserand states, it’s more about the overall exposure. He explains you can diffuse small amounts for limited periods of time so long as there is good ventilation and your cat has the freedom to leave the room if it wants.7
Tisserand explains cats almost completely lack important liver enzymes that humans possess, which are important in the metabolism of many essential oil constituents. Therefore, there is a theoretical risk of increased toxicity to cats. However, this is likely to be from ingestion or topical application of large quantities of neat essential oils, not from inhalation.7
Origins of essential oils being unsafe to use on cats
I feel a little like Melissa Shelton who finds it incredibly frustrating when others perpetuate claims about feline physiology and metabolism without any true understanding or reference to their concerns.8
I totally concur with Shelton when she states that she respects those who would like to take the cautionary path and avoid use of essential oils with cats; however, we do need to be able to discriminate facts.
The misconception that cats are deficient in liver enzymes responsible for metabolizing certain essential oil constituents, she explains, may have started with a 1972 research article examining the toxicology of benzyl alcohol to cats.8
This original paper examined the toxicosis in cats from the use of benzyl alcohol in lactated ringer’s solution. This is most likely where the precaution of using any substance with phenols came about. By the way, if we look closely at this study, benzyl alcohol was injected into the cats.9
The problem is that there are very few studies examining feline drug metabolism.
I found one interesting paper, published by Dr Michael Court in 2014, which explains that many pharmacokinetic studies indicate that drugs such as acetaminophen, propofol, carprofen, and acetylsalicylic acid (aspirin) are eliminated significantly more slowly in cats compared to dogs and humans.
Cats lack the major phenol UDP-glucuronosyltransferase (UGT) enzymes that are involved in the elimination of these drugs. It’s not to say that cats cannot eliminate these drugs, it is just that it takes longer.9
Essential oils with high phenol content include basil, cinnamon leaf, clove bud, oregano, savory and thyme.
Court explains that benzyl alcohol and benzoic acid are compounds regularly added to drugs as preservatives. Benzyl alcohol is metabolized to benzoic acid and then excreted as glucuronide or glycine conjugate in most species. Cats are not able to glucuronidate benzoic acid, but can glycinate it although relatively slowly. It has therefore been recommended that the amounts of benzyl alcohol and benzoic acid used in pharmaceutical preparation for cats be minimized.9
Shelton does not mince her words when she states if essential oils were as toxic as they are around cats, ‘cats would be dropping over dead all over the world.’ 8
Shelton asks the question, can cats metabolize essential oils? She states yes, however cats have a much slower elimination time to dogs and other animals.8
Many citrus oils are also listed as toxic for cats. I am assuming this came about because of some old studies examining the effects of extremely high doses of a flea repellant containing limonene, one of the main constituents found in many citrus oils.
It appears to originate from some 1980s study examining the toxicology of an insecticidal dip containing d-limonene on cats. The study examined the effects of a single dermal application of a commercial insecticidal dip containing 78.2% d-limonene in cats. No clinical signs or toxicosis was reported at the manufacturer’s recommended concentration. However, at 5 times the recommended concentration, clinical signs were mild and consisted of hypersalivation of short duration, ataxia, and muscle tremors resembling shivering. At 15 times the recommended concentration the same clinical signs lasted up to 5 hours.10
Other papers published around this time also began stating that cats are susceptible to poisoning by insecticidal products containing limonene and signs of toxicosis including hypersalivation, muscle tremors, ataxia, depression and hypothermia.11
What everyone fails to report is that the study involved extremely high topical doses well above recommended concentrations for cats.12
The study, by the way, also confirmed that d-limonene proved to be very toxic to all life stages of the cat flea.12
However, as Shelton points out, it would appear that what was specifically referring to a study regarding a flea repellant product containing d-limonene became a blanket statement to say ‘no citrus oils ever’ for cats.8
I concur with Shelton who sympathizes with all those who are concerned that they have unknowingly injured their cat with the use of essential oils.
However, she urges us to examine all the other factors such as diet and other environmental chemicals in our house which may compromise the health of our cat. She urges us to take a stance of critical evaluation, instead of fear-based and poorly documented reports and concerns.8
Conclusion
Let’s make a summary of some of the good advice regarding the use of and diffusion of essential oils around cats:5,13
• Always store essential oils away from your cat.
• Always ensuring there is sufficient ventilation in the room
• Ensure the diffuser cannot be reached by your cat.
• Ensure your cat is able to have access to leave the area if needed be.
• Always wash your hands after handling essential oils before touching your cat.
• Always use pure high quality essential oils.
• Looking out for signs of an intolerance to an essential oil such as squinting, excessive drooling, scratching, increased breathing rate and lethargy.
• If you notice any strange behaviour, from your pet or your pet accidently ingests essential oils, contact your vet immediately.
References
- https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-informaiton/feline-health-topics/common-cat-hazards-0
- https://vetmed.tamu.edu/news/pet-talk/a-scent-sitive-subject-essential-oil-diffusers-and-your-cat/
- MacLeod E. Essential oils for cats – the complete essential oil guide for cats! Protect your beloved family member from diseases and illnesses by using essential oils. Recipes included! Spirit Publishing, 2015.
- Ross M. Essential oils for cats – safe & effective therapies and remedies to keep your cat healthy and happy.
- https:/www.floraandfauna.com.au/blog/essential=oils-and-your-pets?
- Hendley S. Essential oils and oil diffusers could be harming your pet. Downloaded on 4 April 2022 from https://www.abc.net.au/everyday/are-your-essential-oils-and-diffusers-hurting-your-pet/100107687
- Tisserand R. Cats and Essential oil safety. Downloaded on 4 April 2022 from https://tisserandinstitute.org/cats-essential-oil-safety/
- Shelton M. The science behind cats and essential oils. Downloaded on 4 April 2022 from http://www.mcconnellsburvet.com/the-science-behind-cats-and-essential-oils
- Court MH. Feline drug metabolism and disposition: pharmacokinetic evidence for species differences and molecular mechanisms. Veterinary Clinics: Small Animal Practice. 2013;43(5). doi: 10.1016/j.cvsm.2013.05.002
- Hooser SB et al. Effects of an insecticidal dip containing d-limonene in the cat. Journal of the Veterinary Medical Association, 1986;189(8):905-8.
- Hooser SB. D-limonene, linalool and crude citrus oil extracts. Veterinary clinics of North American: Small animal practice. 1990;20(2):383-385. doi: 10.1016/S0195-5616(90)50032-7
- Hink WF, et al. Toxicity of d-limonene, the major component of citrus peel oil, to all life stages of the cat flee, Ctenocephalides felis (Siphonaptera: Pulicidae) Journal of Medical Entomology. 1986;23(4):400-4. doi: 10.1093/23.4.400
- https://www.pdsa.org.uk/pet-help-and-advice/looking-after-your-pet/kittens-cats/cats-and-essentialoils
