Aromatherapy | The Art & Science of Using Plant Oils in Treatment

Aromatherapy: The Art & Science of Using Plant Oils in Treatment |Genevieve Vincent

Wild Seed School of Herbal Studies, 2018

Webster’s Dictionary describes aromatherapy as “the use of aroma to enhance a feeling of well-being”. Most of us practice aromatherapy unwittingly in our everyday lives. Enjoying fragrant flowers, cooking with aromatic herbs, taking scented baths or burning incense are some common examples of when pleasant smells can be mood altering and therefore assist in improving one’s health and vitality. Aromatherapy uses extracted plant oils which are named essential, volatile or ethereal oils. Aromatherapy is considered a holistic practice, as aromatic plants and oils are seen by many to be beneficial for the mind, body and soul.

Aromatherapy traces its roots to the most ancient healing practices of human civilization. The plants which are now used to make essential oils have been used for thousands of years before the distillation process was invented. The Egyptians were well aware of the value of aromatics on the psyche as well as on the body. Hieroglyphs depict high priests/priestesses and alchemists blending aromatic substances for various libations and rites through perfumes, mummification, infused oils, medicinal pills, ointments, and incense. Archaeologists have found that by the 3rd century BC, Egyptian and Mesopotamian civilizations were using primitive distillation devices. The Greek and Roman empires were also well versed in the use of herbal therapies; artifacts have suggested that they also had early distillation devices. Greek soldiers would carry a medicinal ointment made from myrrh and olive oil with them into battle to treat wounded soldiers. The Arab physician Avicenna is credited with the perfection of distillation by the addition of cooling coils to the basic still. Among many contributions to holistic medicine, it is also speculated that he was responsible for the first essential oil: Rose Attar. By the 12th century, essential oils (“the perfumes of Arabia”) were famous in Europe. Crusading knights carried these precious perfumes as well as the knowledge of methods used to distill these oils. In medieval times, wealthy houses would have their own private distillation rooms for making essential oils (known as “chymical oils”). Oils could also be purchased from local apothecaries. Aromatic bouquets of herbs called “tussy-mussies” were hung in the home to dispel moths and were carried to protect oneself from diseases such as the plague. The wordaromathérapie was first coined by French chemist Dr. René-Maurice Gattefossé in 1928. According to tales, Gattefosse experienced a laboratory explosion while conducting research for his family’s perfume company. He then allegedly dunked his badly burnt hand into a vat of lavender oil, the closest liquid he could find. The relief he felt sparked his interest in the medicinal use of essential oils. Today, the use of aromatherapy is increasing in popularity as more people become aware of the negative effects of pharmaceuticals and conventional medical practices.

Every essential oil exudes its own fragrance and personality. Within these precious oils, of which no two are alike, is the essence of the plant; its concentrated life-force. This can be beautifully demonstrated with Kirlian photography. Almost all flowers, seeds, grains, resins, roots, leaves, woods, and barks contain at least a smidgin of essential oil. Some plants will yield multiple oils such as the orange, (Citrus sinensis) which produces a different scent in its peel, leaves, and flowers. Many essential oils are used by their plants to attract beneficial insects, or ward off undesired ones. Plants also use oils to protect themselves against bacterial and fungal infections and to protect against excessive heat or cold. It is thought that plants which have endured stressful conditions will produce more protective oil, and therefore contain more medicine. Due to the harsher conditions they face, wild plants tend to have greater concentrations of medicinal potency than cultivated ones. The scent of a plant, and its pheromones, are also a form of communication with other plants. Apparently the presence of essential oils in a room will trigger house plants to grow and flower more vigorously! While each essential oil is credited with its own specific properties, to a greater or lesser degree they all impart antibiotic, antiseptic and anti-inflammatory benefits. Certain oils are known to improve circulation, have an analgesic effect, bring warmth, or have a cooling effect on the skin. Some have the ability to relieve fluid retention, promote sweating, boost the immune system, heighten or lower blood pressure, reduce pain, deodorize, stimulate cell re-growth. Others are even suggested to be anti-viral. Psychologically, aromatherapy may benefit motivation, mood, memory, creativity, arousal, nervous system issues and more..! The two main mood-altering effects of aromatherapeutic oils are considered either stimulating or calming, the latter having positive virtues for our immune systems which are often undermined by stress and tension.

Essential oils, when properly administered, will produce no harmful side-effects. Inhalation, topical application and bathing are the three main methods used to encourage the entry of essential oils into the body. On inhalation, the oil molecules are received by the receptor cells in the lining of the nose, which transmit electrochemical signals to the brain. The olfactory centre in the brain then stimulates the release of neurochemicals into the blood to be transported around the body. Molecules inhaled into the lungs may pass into the bloodstream and be dispersed in the same way. The molecular structure of essential oils enables them to penetrate the skin much more readily than heavier fatty oils. When applied topically, essential oils will permeate into the pores and hair follicles, then enter the circulatory system, and connective and lymphatic tissues. Use in bathing is a form of both inhalation and absorption by the skin. Some common aromatherapy uses include massage, hair/scalp treatment, cream/oil/lotion/liniment/ salve, room or body spray, hot or cold compress, sitz/foot/hand/full-body bath, mouthwash, diffusion, inhalation, perfume, herbal sachets, neat application (seldomly), and they can also be taken orally (with caution). The nature of someone’s complaint, their personality, lifestyle, eating patterns, relationships, and state of mind should all be considerations when administering aromatherapy.

Certainly a fun and creative aspect of aromatherapy notably (“note” the forthcoming pun) lies in formulations! When two or more oils are blended to attain a common goal such as imparting a certain mood or treating a specific ailment, it is known as a synergistic blend. There are a few common guidelines used for making nice-smelling blends which divide oils into categories such as: aromas, botanical families, and notes. Floral, woodsy, earthy, herbaceous, minty, medicinal, spicy, oriental, and citrus are the main aromatic groupings. Oils in the same categories tend to compliment each other, and some suggested mixing and matching goes as follows: floral likes to blend well with with spicy, citrus, and woodsy, woodsy blends well with all categories. Spicy and oriental oils blend with floral, oriental, and citrus. Minty oils blend with citrus, woodsy, herbaceous, and earthy. Oils extracted from the same botanical family will often blend and work well together. The “note” of an essential oil is established by how quickly it evaporates. These notes are based on the musical scale and are referred to as top notes, middle notes, and bass notes (spelled base in perfumery). Oils that evaporate the quickest, usually within 1-2 hours, are called “top notes” and will be the first impression when you smell the blend, oils that evaporate with 2-4 hours are considered “middle notes”, these are the harmonizers, and the ones which take the longest time to evaporate are referred to as “base notes”, sometimes lasting up to a few days, these notes will be the lingering fragrance. The idea is to choose an oil from each note category so as to have a well-rounded scent. Generally, blends will contain 30% top note oil, 50% middle note oil, and 20% base note oil. With the exception of a few oils such as lavender and tea tree, essential oils should always be diluted into water, alcohol or a base oil. This is because they are extremely concentrated, may burn your skin if undiluted, and because of their tendency to rapidly evaporate. Fatty oils, into which these volatile oils are usually mixed, are called “carrier oils” or “base oils”. It is important to use high-quality nut or vegetable oils with good penetrative qualities. Animal fats may also be used. Carrier oils all have their own set of nutrients and therapeutic qualities.

Extraction techniques vary depending on where the oil is situated in the plant. The fragrant oils are located in tiny sacs in or on the plant’s tissues. Distillation is usually the preferred (and most common) method by which essential oils are extracted. Arguably, distillation is the only method that produces a “true essential oil”. Oils obtained by other methods would be correctly defined as “essences” or “absolutes”. Plants which have oil glands readily accessible on the outside of their leaves (such as those of the Labitiae family) are good choices for distillation. In plants such as tea tree or myrtle, the plants may require bruising before distillation. Distillation involves either placing the plant material into water which is then brought to a boil (a process called direct distillation), or by suspending the material on a rack and heating the water beneath it so that the steam passes through it (steam distillation). In either method, the heat from the water bursts the cells containing the volatile oil; the oil vaporizes and mixes with the steam and is carried upwards. The steam and vapour is then passed through cooling coils to be condensed and re-liquified. In almost every instance the oil is very light, and will float on the surface of the watery distillate. The essential oil is separated and the left-over herbal water is known as a “hydrosol”, “hydrolat” or “flower water”. Pressure, temperature, and time must be adjusted for each specific oil, so as to obtain the maximum constituents without burning the oil. Plants of the citrus varieties lend themselves to the simplest method of extraction called expression. The oil glands of these plants are usually visible on the surface of their skins without the need for magnification. Expression can be done either by hand or mechanically, and involves squeezing or scraping the peel and rinds of the fruit. Oil is then collected with a sponge and squeezed out when saturated. The cold-pressing method is also used with these types of fruit, and involves shredding the peel, mixing in a small amount of water then cold-pressing the material until the oil floats to the surface of the water. By using turbulence and alcohol it is possible to to separate the essential oils or absolutes, from an oil infusion. Using this technique is called defleurage. A variation of this method is called enfleurage, and is achieved by crushing flowers between sheets of glass smeared with fat (traditionally pork or beef fat), after a time the volatile oil absorbs into the fat, the flowers are continaully replaced with fresh flowers until the fatty oil is satisfactorily saturated with essential oil. An alternative method can be done with an oil such as olive oil, and sheets of muslin cloth. The flower’s oil is then separated from the fat or oil using the same method described above for defleurage. Essential oils obtained in this way tend to be of superior quality compared to those obtained by distillation, and are very expensive. This was one of the earliest forms of oil extraction, however the fragrant oil would be left in the fat. This is known as a pomade. In the case of especially delicate flowers, solvent extraction is often used. Fresh flowers are placed in a centrifuge with a solvent until the plant’s oils and waxes separate from the remaining material. The oils would then be vacuum-distilled at a low temperature in order to separate them. Solvents used include hexane, ether, and carbon tetrachloride. These are very toxic and can never be completely eliminated from the essential oil. In some instances, alcohol is also used as a solvent. The resinoid method is used for extracting fragrant resinous substances such as benzoin and larch. The resin is mixed with either alcohol or toluol/toluene, heat is introduced, then the solvent is evaporated. Alcohol is preferred as some solvent will remain in the final product. Extraction is also possible with the use of pressurized carbon dioxide or butane. Essential oils extracted by this method differ distinctively from those which have undergone distillation: they have a higher “top note” and a lower “base note”. Whether they are safe for therapeutic use has not been established.

Essential oils are powerful substances. There are certain hazards which anyone using essential oils should be aware of, it is recommended to research every essential oil that is unfamiliar before using it. There are many oils which are not recommended for certain people or in certain instances. Some essential oils are contraindicated for children or people who are susceptible to epilepsy, have heart or kidney problems, have high or low blood pressure, are pregnant or breastfeeding, or have sensitive skin. Essential oils can also be toxic with prolonged exposure, cause photosensitivity, irritate the skin, and possess narcotic qualities. The use of pennyroyal oil as an abortifacient for example, has led to poisonings and deaths. Oil of clary sage is supposedly not recommended with the consumption of alcohol because this combination may cause nightmares. Another consideration is to purchase good quality, pure essential oils; for therapeutics, a synthetic oil will not do! Synthetic oils should never be consumed internally. An essential oil’s shelf life is usually about 1 year, however citrus oils should be kept under refrigeration. Lastly, essential oils are flammable!

Aromatherapy has the considerable benefit of being not only a healing treatment but also an enjoyable experience! The need for human touch is present in all of us, and so is communion with nature! Aromatherapy has the power to deepen our connections with loved ones, bring solace to our hearts, and help us develop rituals that bring more meaning to our lives. Simply follow your nose!



  1. Everyday Aromatherapy, by Karen Philip
  2. Aromatherapy an A-Z, by Patricia Davis
  3. Complete Aromatherapy Handbook, by Susanne Fischer-Rissi
  4. The Encyclopedia of Psychoactive Plants, by Christian Ratsch

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