Our Concept of Aromatherapy for Companion Animals

As aromatherapy for companion animals is fundamentally based on information practiced in humans, it is essential to grasp the reality of human aromatherapy information. Aromatherapy is one of the complementary or alternative therapies using aromatic substances of plants. The terminology “Essential oil” may be translated “oil composed of plant essence” or “oil essential to our lives”. However, it is not necessity for animals, and it doesn’t belong to fat or lipid, in spite of having the name “Oil”. It is the fat-soluble organic chemical compound with little water solubility, and highly concentrated by artificial means.

Aromatic substances used in our aromatherapy practice, have not been recognized as essential for plants to live and not considered as substances absolutely necessary for them. Because, they are secondary metabolites of plants. However, recent studies have found that these aromatic substances and resins used for aromatherapy are immune substances with humoral immunity inherent to plants. These substances for plants are now recognized to be essential for self-defense to keep on living. Nevertheless, these organic chemical compounds are nothing but xenobiotics (substances foreign to bodies of companion animals) equal to poisons or drugs.

Recently, the information on risks of aromatherapy to cats is beginning to penetrate gradually, and the aromatherapy for dogs is now quite popular. In the household, however, not only dogs, but cats, birds and other small animals (including aquarium fish and pet insects) live together, in many instances. Practice of aromatherapy for dogs in these situations must take a proper care of other pet animals.

This year 2013, the Ministry of the Environment proposed Super Cool Biz campaign, recommending the use of aromatic fabric softener and antiperspirant in washing fabrics. A flood of complaints claiming “aromatic chemical compounds can make more people sick” is recently pressing the Ministry of Environment to deal with the problem. Proper care must be taken not only for people, but for companion animals living with us. Experiments on mice, especially in the use of certain synthetic fragrance induced the phenomenon of atrophying male testes, according to a research report.

One of the causes for sick building syndrome recently attracting attention includes d-limonene and hexanal, that are components of essential oils.

Looking from the standpoint of global environment conservation, we think that the use of essential oils extracted from wild plant substances, such as rosewood, sandalwood, atlas cedarwood, etc., or essential oils extracted from wild plants and flowers should be avoided as much possible, as it can cause drastic decrease of natural plant species. Companies selling essential oils say that to avoid environment issues they plant 2 saplings when 1 tree is cut down, in case of Brazilian rosewood for instance. But, in the field, the area of forest is decreasing rapidly. Explanations by those companies are not revealing the fact, and rosewood is listed as endangered by the Washington Convention (CITES). In India, also, the export of sandalwood is now regulated.

Also, it has been indicated that these essential oils can include synthetic fragrances. Monoterpene hydrocarbon, an ingredient of scent of the forest and also a compound hard to be metabolized, could cause a great risk for cats, as it is highly volatile and has almost no aqueous solubility, easy to penetrate into cat bodies. It is one of the reasons why scent of the forest and lemon scent are harmful to cats.

We have to realize that essential oil ingredients entered into the body of companion animals are foreign objects for the living system, and the substances to be discharged out of the body as soon as possible, by changing it to aqueous soluble substances (via metabolization), by urine or feces or by dissolving in exhaled breath. Otherwise, we cannot safely utilize these xenobiotics. That is why aromatherapists must have certain knowledge of drug metabolism and definite awareness on physiology/metabolism of companion animals living together with us.

The modern term “aromatherapy” started to be used and in Europe many specialists called aromatherapists came into the world, releasing various books and reference materials. Before academic researches began, early aromatherapists without the awareness mentioned above listed in their publications the effects as herbs of such plants, making them out to be the effects of essential oils. These books have been used as bibles by many aromatherapy schools even now.

Almost every paragraph of an essential oil in a general EO monograph includes possibility of application of the oil to a wide variety of diseases and symptoms. People infuse plant materials and use beneficial effects as herb tea. The main ingredients of infusion and herb tea consist of water soluble ingredients, excepting minute fragrance components. On the other hand, most of the main ingredients of essential oils contain fat-soluble components, and water-soluble components are extremely limited. On top of that, we have to be aware that the essential oils are highly concentrated artificially.

When organic compounds of 100% xenobiotics such as essential oils enter the animal body including us humans, the defense mechanism instantly start working and dealing with the problem to discharge these substances out of the body, involving various enzymes and protein substances called transporters, kicking livers into high gear.

Metabolic enzymes produced in our body start working on these organic compounds at the site of absorption, but the No.1 organ for detoxification and metabolism is liver. Without some knowledge on activity of enzymes of the liver, we can never solve the magical mystery of aromatherapy.

Aroma schools now teach “not to practice aromatherapy on people under the influence of alcohol”. Many qualified aromatherapists know such information. But, as it stands now, almost no schools do not explain why. Yes, as the 2 xenobiotics, alcohol and essential oil ingredients, entered into the body at the same time, the enzyme activity in the body is inhibited each other by two substances that use the same enzyme. So, the enzyme called alcohol dehydrogenase for metabolizing alcohol and the enzyme for detoxifying acetaldehyde cannot function, and as a result, alcohol ingredients stay poorly metabolized remaining in the body for a long time, and the hangover phenomenon is induced. This is human biology, though, similar phenomena might occur in the body of animals.

Aromatherapists must be aware of the possibility of inhibiting enzyme activity mentioned above, just by whole-body massage with carrier oil containing essential oils of low concentration such as a few percent.

It is often said that antihypertensive drugs and grapefruit juice cannot be taken together, and it has the similar reasons. As furocoumarin contained in the juice interact with drugs and restrict the activity of P-glycoprotein playing as a role of transporter for drugs not to enter the body, like a defensive screw pump, drugs get one-two punch and the blood concentration jumps up. Drug potency or bioavailability gets too much, and it causes blood pressure dropping too much, and people cannot stay upright. The amount of furocoumarin contained in a glass of juice is extremely small. Furocoumarins are contained also in citrus essential oils extracted by the expression method.

Xenobiotics, the secondary byproduct of plant metabolism, not only contain substances inhibiting enzyme activity in the animal body, but often cause an increase in the activity of enzymes. In the area of herbs and Chinese herbal medicine, the study on interaction with Western medicine has been carried out to a certain degree, but in essential oils the study has just begun, and academic reports are still very limited. In the short term, a report has been made that essential oil ingredients inhibit metabolism enzyme activity of the phase 1 (the first stage) of the liver, and that they have the potency to increase “bioavailability; drug efficacy” of the Western medicine. However, the study on the use of essential oils in the long term is yet to be defined, and we have no clues on the details.

An animal experiment in mice showed that essential oils can affect the liver enzyme activity, inhibiting in the short term, however enhancing over the long term. You may think that inhibiting the metabolizing enzyme activity to enhance the bioavailability of medical drugs may be beneficial to our animal bodies; however, if the drugs have strong side effect, undesirable events may occur. Advisory information about interaction between Essential Oils & Drugs has been provided at The Medical Center of Maryland University.  

Further Drug interaction events include herb medicine as well. We only talked about inhibition of metabolism enzymes, so now let us give you an opposite example. The Saint John’s Wort herb material has been said to be good for alleviating depression in young females.  Given those who take this kind of herb tea as a routine use began to have an acute asthma exacerbation, the drug bronchodilator will be metabolized rapidly by enhanced enzyme activity, and the patients cannot have effective blood concentration of the drug, leading to be a life-or death matter.  People may often have good intentions; however these kind of drug interactions do patients much more harm beyond all imagination.   

Imagine a qualified aromatherapist advising their clients about the effects of certain essential oils without any knowledge of liver enzymes. And if the client has to undergo certain medication due to health problems, can you imagine what happens next? It should be obvious that “Ignorance is inexcusable”. 

To compound matters, liver enzymes differ greatly in type and number, depending on animal species. It is very obvious that Human aromatherapy cannot be applied to animals. Wild feline species, including domestic cats have genetic defect to bio-synthetize very important liver enzyme to metabolize essential oil components that are highly fat soluble material; xenobiotics. Female domestic cats have lesser number of enzymes, therefore, it has been indicated they have greater aromatherapy risks than males (Shah,S.S. 2007. J.Vet Pharm & Ther,30) Recent animal research revealed the mutation parts of the gene in feline species, and brown hyena and northern elephant seal also showed inactivating gene mutations (Binu Shrestha, et al. PLos ONE, 2011/Vol.6).  Ferrets and certain civets have low activity of enzymes (Court,M.H.(2002):J Vet Pharm &Ther,24). However, the gene variation in these species have been unexplained, and the reports only refer to the poor action in the liver enzymes.

Animal Aromatherapy information has been inundated in town. “Dogs/Cats get healed by aromatherapy” concept is capitalized by various educational institutes.  Only efficacy or merits of aromatherapy are highlighted in news media and magazines as well. However, even in dogs, it would be lying if one said most essential oils are safe. The popular Tea tree essential oil has neural toxicity in animals, and it has been recommended not to use for animals regardless of any reasons. Similarly, Hydrosols (floral water collected as by-products in extracting essential oils by steam distillation, also known as herb water) that contain phenol or ketone involve risk. Safety has not been established in these floral water materials. Dr.Kahn of National Animal Poison Center also says no one knows whether hydrosols are safe for cats, because these materials are rarely analyzed. The hydrosols our association uses go through the component analysis by the joint-study university for risk prevention purposes.      
Beneficial effects of essential oils have been reported in scientific journals on daily basis. However, the author of “Aromatherapy Science”, Maria Lis-Balchin says that the number of scientific reports on essential oils that prove real merits of essential oils, is very limited. Because many researchers use essential oils without analysis data in the market, believing they are 100% genuine oils, and they rarely analyze the oils used in their experiments by themselves or rarely request for proper analysis before the start of their experiment. And, their reports are based on the theory that main component plays the role of medical effects of such essential oil, and data collection is made using the main component at the same time. Many researchers ignore the presence of isomers in various components. They often conduct experiment using racemic compounds, and this presents the fact objectively that researchers are using artificial fragrance materials in their experiments. These raise fundamental doubts about the evidence of those experiments. In the event where psychological actions are involved as in humans, we cannot conclude that the medical actions of essential oil main components are the overall actions of such essential oil. Actions of essential oils directly affect animals, since no intimations can be given in case of animals.

Before that, we have to acknowledge that the ratio of components varies greatly depending on various conditions, even in true lavender oil, Lavandula angustifolia. No one can generalize various lavender oils to state “Lavender oils have sedative effect.” This can involve a risk in a way.  It may be an extreme expression, we can only state that this kind of result is obtained, when experiments are made using lavender oil with such components. There are variety of species and breeds in lavenders, and the plants are easy to intercross, too. It has been proved that some essential components isomers show sedative action and their enantiomers have stimulant action on the contrary. The fact that actions can be reversed depending on difference of component’s optical isomers is gradually clarified.

Most of medical effect experiments of essential oils are data amassment using animals. However, we think that scientifically proven essential oil merits for companion animals are very limited. For instance, increasing blood flow of a dog with loin pain and giving it aroma massage in order to ease the pain, can worsen the symptom, in case of leprosy type I hernia of nucleus pulposus. As Maria Lis-Balchin mentioned in “Aromatherapy Science”, that massage without using essential oils is itself beneficial, for a healthy dog walking with the guardian, light whole-body massage when relaxing can be much safer and beneficial physically and mentally. When a dog gets old with poor limb function, we have to take much precaution for using essential oils.

Much the same is true on the use of essential oils for skin allergic symptoms. For instance, in the cases of yeast form fungus ear infection in dogs, which is now considered one of food allergic skin responses, essential oils work better in some cases and hydrosols work better in others, depending on the type of pathogens. Among pathogens, some require fat to grow, some do not and cannot proliferate under oily circumstance. Therefore, easy application of essential oils or hydrosols in haste can end up advancing the symptom, from simple thinking such as looking skin itching or lesion progressing. When we practice aromatherapy to animals, we have to attempt to get right diagnosis as much as possible, and judge the necessity of aromatherapy. Otherwise, we can face an unexpected result.

In 1867, European Pharmacopoeia already has the description of essential oils, and Bennet, a British doctor reported that he applied aroma massage with essential oils to treat diseases in his hospital.  In 1901, Hale-White and the group used essential oils for treating arthritis which was written in his book. It is rather reasonable to think that information by Hale-White and the group is the base of medical aromatherapy, instead of so called “Aromatherapie exactement” written by a group of medical practitioners. Gatti&Cajola, or Paolo Rovesti, Italian doctors, also started study of essential oils as medical treatment, so France is not the birthplace or the place of establishment on medical aromatherapy. Maria Lis-Balchin provides a critique in her book regarding “Aromatherapie exactement”, saying that as the editors made corrections in French that information never circulated around the world, and on top of that, Lis-Balchin is mentioning the medical treatments written in the book are rather risky.

Qualified aromatherapists often tell that they leaned at schools on the public health insurance coverage on aromatherapy in France and Belgium. Recently in England, only when doctors acknowledge its necessity in the primary care, this alternative treatment was once covered by the public health insurance. But in actuality, the health insurance system has been in red, and cases of receiving aromatherapy treatment with essential oils covered by the health insurance are hardly known. In addition, there are no actual cases where public health insurances have been officially used for such alternative medicine in Europe.

Dr. Teruo Hirose who translated the term Alternative Medicine into Japanese as “Daitai Iryo” is famous for his book called “Encouragement of Alternative Medicine”. Dr. Hirose was Professor of New York Medical College, Clinical Surgery, and after his retirement he traveled all over the world and wrote a book on alternative medicine of the world titled “Report on World Medical Scenes”. In the section of France and Belgium, he never touched upon aromatherapy.

As for public health insurances, French Embassy of Japan denies public insurance coverage of alternative medicine, but some big merits and demerits are officially announced as the meaning of medical grade essential oils of France. Henri Pouchon operates a farm and produces in his farm annually distilling 50 tons of good quality lavender and lavandin essential oils. He publicly announces the lavender essential oil exported from France to be ballooning to 250 tons as terming own farm-made product. It is the reason for placing a big question mark to French essential oils considered to be of medical therapeutic grade.

It is not hard to imagine the risk of massages given as “healing method” to small companion animals using diluted recipes for human aromatherapy or given as a drink. It is the same in human aromatherapy, the existence of data is very important on skin sensitization and toxicity of essential oils for use. We are in the times where animal testing is not simply done. In the event we carry out the test, the ethics board established at each research institution examines whether or not animal abuse is applicable, and we have to submit the data obtained by minimal number of animals for the test. As we cannot perform simple testing toxicity and sensitization of essential oil components, so past data obtained can be very precious reference materials.

Mr. Martin Watt compiled dispersed academic data on skin sensitization and toxicity in one book, and presented the information as ‘Plant Aromatics’. There should be no excuse for practitioners to treat companion animals using essential oils not listed in his publication (English data is now available at http://www.botanical-dermatology-database.info/). Without safety data in conducting aromatherapy, if the animal conditions get worse and adverse effects develop, no excuse will avail. You now understand fundamental practice selecting essential oils with safety data. However, some essential oils often used as food additive have incomplete safety data. If you have to use such essential oils, you must pay special attention.

Qualified aromatherapists seem to show great interest in essential oils with new fragrance and be too quick to use them. They are legally defenseless if accidents happen with essential oils with no data, while testing to amass safety data cannot be performed easily. They cannot even explain the reason why such essential oil is utilized, if customers bring an action against them.

Essential oils and hydrosols are continuing to be used daily, without right diagnoses while information on essential oils in the world has confusions and mistakes, as if healing for people also can be applied to animals. The issue on quality of essential oils and hydrosols can cast a big shadow. Why? Because general aromatherapists purchasing small amount of essential oils have almost no chance to learn about analysis of essential oils. General outline of gas chromatography and mass spectrometry is imperative, but most of them think detailed data can be obtained by analyzing by gas chromatography only. At present, as we are in a difficult time to obtain quality helium gas, we are concerned about the situation because accurate analysis is hard to conduct under such circumstances. Furthermore, even if we ask someone to conduct mass spectrometry, precision of analysis becomes less accurate, without lined up of correct data spectrum of minor components called ‘library’.

As researchers involved in analysis of essential oil components unanimously profess, adulteration is rampant on a global scale for essential oils and hydrosols. What will happen if the product you believe 100% natural is adulterated? Hydrosols are getting quite popular as cosmetics recently, so the products which were mostly discarded up until now are now on the market. At the stage of producers, potassium sorbate, paraben, phenol, ethoxyethanol, etc. are blended in to preserve them from decay.

After that, an European analyst professed that making adjustment with citric acid to the pH value indicated in aroma reference book is commonly done. In addition, there seem to be very few hydrosols processed in sterile procedures, which can cause microbial contamination. The pH level of hydrosols are largely affected by the pH value of the soil to cultivate plants and the pH value of the water to be used for distillation. It may not be possible to show a certain pH level indicated in reference books on hydrosols.

While right aroma products are extremely difficult to be obtained, it is essential to apply aromatherapy with full awareness of its harmful effects, based on careful determination whether or not to apply treatments by essential oils or hydrosols for companion animals under right diagnosis, as mentioned earlier.

In human aromatherapy, wide variety of essential oils are used. For animals, only a handful of right essential oils academically proven to be effective to animals can temporarily ease many symptoms to a certain degree. However, advices on overall parenting are also unavoidable factor, since it is proved that aromatherapy alone cannot handle most cases, for fundamental improvement of various symptoms. When applying essential oils or hydrosols to animals, it is a must to check that such animals are not under medication for some diseases. In essence, we believe that aromatherapy for companion animals is a complementary or alternative medicine to practice with the greatest possible care, to get greatest possible effect in short period to time in adequate concentration and frequency.

As long as we allow effects and efficacies to bodies and mind either in humans or animals to be appreciated, we believe that it is our obligation to explain harmful effects, and that it cannot be separated. Aromatherapy to use essential oils handled as general merchandise is xenobiotics possible to develop strong pharmacological effects.

For future proper advancement of aromatherapy, researchers in various fields such as those involved in human and animal medical care, chemists, biochemists, pharmacologists, knowledgeable specialists in the field of botany and zoology, including those involved in present aromatherapy, and knowledgeable specialists in such information because of a key factor related to essential oil business, all these specialists must cooperate and move ahead, exchanging information and fairly acknowledging effects / efficacies, adverse effects and so on. Otherwise, we believe that direction will get lost and that it cannot deny the possibility of working against the welfare of people and animals.

Koki Tanabe DVM
Kazuko Tanabe DVM 
Japan Animal Aromatherapy Association

((This manuscript is reviewed by Martin Watt))

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