Encyclopedia of Essential Oils: The complete guide to the use of aromatic oils in aromatherapy, herbalism, health and well-being.

Treasures from the East

Natural aromatics and perfume materials constituted one of the earliest trade items of the ancient world, being rare and highly prized. When the Jewish people began their exodus from Egypt to Israel around 1240 BC, they took with them many precious gums and oils together with knowledge of their use. On their journey, according to the Book of Exodus, the Lord transmitted to Moses the formula for a special anointing oil, which included myrrh, cinnamon, calamus, cassia and olive oil among its ingredients. This holy oil was used to consecrate Aaron and his sons into priesthood, which continued from generation to generation. Frankincense and myrrh, as treasures from the East, were offered to Jesus at his birth.

The Phoenician merchants also exported their scented oils and gums to the Arabian peninsula and gradually throughout the Mediterranean region, particularly Greece and Rome. They introduced the West to the riches of the Orient: they brought camphor from China, cinnamon from India, gums from Arabia and rose from Syria, always ensuring that they kept their trading routes a closely guarded secret.

The Greeks especially learnt a great deal from the Egyptians; Herodotus and Democrates, who visited Egypt during the fifth century BC, were later to transmit what they had learnt about perfumery and natural therapeutics. Herodotus was the first to record the method of distillation of turpentine, in about 425 BC, as well as furnishing the first information about perfumes and numerous other details regarding odorous materials. Dioscorides made a detailed study of the sources and uses of plants and aromatics employed by the Greeks and Romans which he compiled into a five-volume materia medica, known as the Herbarius.

‘Lentisco del Peru’ (Mastic Tree) from Durante’s Herbario Nuovo, 1585. Gums and oils were regarded as highly prized trade items throughout the Mediterranean region

Hippocrates who was born in Greece about 460 BC and universally revered as the ‘father of medicine’, also prescribed perfumed fumigations and fomentations; indeed ‘from Greek medical practice there is derived the term ‘iatralypte’, from the physician who cured by the use of aromatic unctions’.4 One of the most famous of these Greek preparations, made from myrrh, cinnamon and cassia, was called ‘megaleion’ after its creator Megallus. Like the Egyptian ‘kyphi’, it could be used both as a perfume and as a remedy for skin inflammation and battle wounds.

The Romans were even more lavish in their use of perfumes and aromatic oils than the Greeks. They used three kinds of perfumes: ‘ladysmata’, solid unguents; ‘stymmata’, scented oils; and ‘diapasmata’, powdered perfumes. They were used to fragrance their hair, their bodies, their clothes and beds; large amounts of scented oil were used for massage after bathing. With the fall of the Roman Empire and the advent of Christianity, many of the Roman physicians fled to Constantinople taking the books of Galen, Hippocrates and Dioscorides with them. These great Graeco-Roman works were translated into Persian, Arabic and other languages, and at the end of the Byzantine Empire, their knowledge passed on to the Arab world. Europe, meanwhile, entered the so-called Dark Ages.

Alchemy

Between the seventh and thirteenth centuries the Arabs produced many great men of science, among them Avicenna (AD 980‒1037). This highly gifted physician and scholar wrote over a hundred books in his lifetime, one of which was devoted entirely to the flower most cherished by Islam, the rose. Among his discoveries, he has been credited with the invention of the refrigerated coil, a breakthrough in the art of distillation, which he used to produce pure essential oils and aromatic water. However, in 1975 Dr Paolo Rovesti led an archaeological expedition to Pakistan to investigate the ancient Indus Valley civilization. There, in the museum of Taxila at the foot of the Himalayas, he found a perfectly preserved distillation apparatus made of terracotta. The presence of perfume containers also exhibited in the museum dating from the same period, about 3000 BC, confirmed its use for the preparation of aromatic oils. This discovery suggests that the Arabs simply revived or improved upon a process that had been known for over 4000 years!

Rose water became one of the most popular scents and came to the West at the time of the Crusades, along with other exotic essences, and the method of distillation. By the thirteenth century, the ‘perfumes of Arabia’ were famous throughout Europe. During the Middle Ages, floors were strewn with aromatic plants and little herbal bouquets were carried as a protection against plague and other infectious diseases. Gradually the Europeans, lacking the gum-yielding trees of the Orient, began to experiment with their own native herbs such as lavender, sage and rosemary. By the sixteenth century lavender water and essential oils known as ‘chymical oils’ could be bought from the apothecary, and, following the invention of printing, the period 1470 to 1670 saw the publication of many herbals such as the Crete Herball published in 1526, some of which included illustrations of the retorts and stills used for the extraction of volatile oils.

In the hands of the philosophers, the art of distillation was employed in the practice of alchemy, the hermetic pursuit dedicated to the transformation of base metals into gold, the gross into the subtle. It was primarily a religious quest in which the various stages of the distillation process were equated with stages of an inner psychic transmutation, ‘dissolution and coagulation’: separation (black, lead), extraction (white, quicksilver), fusion (red, sulphur) and finally sublimation (gold or ‘lapis’). In the same way that aromatic material could be distilled to produce a pure and potent essence, so could the human emotions be refined and concentrated to reveal their valuable fruit, or true nature. In this context, volatile oils can be equated with the purified human psyche or ‘quintessence’ of the alchemists, being an emanation of matter and manifestation of spirit, mediator between the two realms.

Alchemy was the bridge across which the rich symbolism of the ancient world – Arab, Greek, Gnostic – was transported into our own era … thus symbolism fell from the rarefied heights into the melting-pot, and began to be tested in a continuous, dynamic interaction with the findings of chemistry.5

The Scientific Revolution

Throughout the Renaissance period, aromatic materials filled the pharmacopoeias which for many centuries remained the main protection against epidemics. Over the next few centuries the medicinal properties and applications of increasing numbers of new essential oils were analysed and recorded by the pharmacists. The list included both well-established aromatics such as cedar, cinnamon, frankincense, juniper, rose, rosemary, lavender and sage, but also essences like artemisia, cajeput, chervil, orange flower, valerian and pine.

The perfumery and distillation industries attracted illustrious names of the day and in the northern countries of Europe, especially at Grassein France, flourishing commercial enterprises sprang up. By the end of the seventeenth century, the profession of perfumery broke away from the allied fields, and a distinction was made between perfumes and the aromatics that had become the domain of the apothecary.

Alchemy gave way to technical chemistry, and with it went the interest in the inter-relatedness of matter and spirit, and the interdependence of medicine and psychology. There developed the idea of combating speculation with logic and deductive reason. With the scientific revolution of the early nineteenth century, chemists were able to identify for the first time the various constituents of the oils, and give them specific names such as ‘geraniol’, ‘citronellol’ and ‘cineol’. In the Yearbook of Pharmacy and Transactions of the British Pharmaceutical Conference in 1907, we find for example:

A pilea of undetermined botanical species has yielded a white essential oil with an odour of turpentine … A small amount of pinene was detected but its other constituents have not yet been identified. This oil is of interest as being the first instance of an essential oil derived from the family Uricaceae.6

It is ironic that this enthusiastic research laid the ground for the development of the oils’ synthetic counterparts, and the growth of the modern drug industry. Herbal medicine and aromatic remedies lost their credibility as methods of treatment went out of the hands of the individual and into those of professionals. By the middle of the twentieth century, the role of essential oils had been reduced almost entirely to their employment in perfumes, cosmetics and foodstuffs.

2. AROMATHERAPY AND HERBALISM

The Birth of Aromatherapy

The term ‘aromatherapy’ was first coined in 1928 by Gattefossé, a French chemist working in his family’s perfumier business. He became fascinated with the therapeutic possibilities of the oils after discovering by accident that lavender was able to rapidly heal a severe burn on his hand and help prevent scarring. He also found that many of the essential oils were more effective in their totality than their synthetic substitutes or their isolated active ingredients. As early as 1904 Cuthbert Hall had shown that the antiseptic power of eucalyptus oil in its natural form was stronger than its isolated main active constituent, ‘eucalyptol’ or ‘cineol’.

Another French doctor and scientist, Dr Jean Valnet, used essential oils as part of his programme by which he was able to successfully treat specific medical and psychiatric disorders, the results of which were published in 1964 as Aromatherapie.

The work of Valnet was studied by Madame Marguerite Maury who applied his research to her beauty therapy, in which she aimed to revitalize her clients by creating a ‘strictly personal aromatic complex which she adapted to the subject’s temperament and particular health problems. Hence, going far beyond any simple aesthetic objective, perfumed essences when correctly selected, represent many medicinal agents.’7

In some respects, the word ‘aromatherapy’ can be misleading because it suggests that it is a form of healing which works exclusively through our sense of smell, and on the emotions. This is not the case for, apart from its scent, each essential oil has an individual combination of constituents which interacts with the body’s chemistry in a direct manner, which then in turn affects certain organs or systems as a whole. For example, when the oils are used externally in the form of a massage treatment, they are easily absorbed via the skin and transported throughout the body. This can be demonstrated by rubbing a clove of garlic on the soles of the feet; the volatile oil content will be taken into the blood and the odour will appear on the breath a little while later. It is interesting to note that different essential oils are absorbed through the skin at varying rates, for example:

Turpentine: 20 mins

Eucalyptus and thyme: 20–40 mins

Anise, bergamot and lemon: 40–60 mins

Citronella, pine, lavender and geranium: 60–80 mins

Coriander, rue and peppermint: 100–120 mins

It is therefore important to recognize that essential oils have three distinct modes of action with regard to how they inter-relate with the human body: pharmacological, physiological and psychological. The pharmacological effect is concerned with the chemical changes which take place when an essential oil enters the bloodstream and reacts with the hormones and enzymes etc; the physiological mode is concerned with the way in which an essential oil affects the systems of the body, whether they are sedated or stimulated, etc; the psychological effect takes place when an essence is inhaled, and an individual responds to its odour. With relation to the first two points, aromatherapy has a great deal in common with the tradition of medical herbalism or phytotherapy – in other words, it is not simply the aroma which is important but also the chemical interaction between the oils and the body, and the physical changes which are brought about.

Herbal Medicine

The practice of aromatherapy could be seen as part of the larger field of herbal medicine, since the essential oil is only one of many ways in which a plant can be prepared as a remedy. Since all essential oils are derived directly from plants, it can be valuable to see them within a botanical context rather than as isolated products. In some ways the use of aromatic oils for therapeutic purposes benefits from being placed within a herbal context not only because it gives us further insight into their characteristics, but because the two forms of therapy are not synonymous, but complementary.

Growing and storing herbs: the woman is scenting the linen chest; from Das Kerfiterbuch oder Herbarius, 1534

Although most plants which yield essential oils are also used in medical herbalism, it is important to distinguish the therapeutic qualities of a particular oil from those of the herb taken as a whole or prepared in another manner. German chamomile, for example, is used extensively in the form of a herbal preparation such as an infusion, tincture or decoction, apart from being utilized for its volatile oil. Chamazulene, a major constituent of the oil, helps to account for the herb’s age-old reputation as a general relaxant and soothing skin care remedy, due to its pain-relieving, antispasmodic, wound-healing and anti-inflammatory activities. For the treatment of nervous conditions, insomnia and dermal irritation or disease, the essential oil is both useful and effective. But although the aromatic principle of the plant plays a central role in its overall character, the herb also contains a bitter component (anthemic acid), tannins (tannic acid), mucilage and a glycoside among other things. The overall effect of the herb is the result of the action of all its pharmacologically active constituents which in the case of chamomile or Matricaria includes the astringency of the tannins and the stimulation of the bitters. The volatile oil is, of course, less concentrated in the form of an infusion, tincture or decoction, the potency of the oil is reduced (and inherently the safety margin increased), thus making the herbal preparation more suited to internal use.

Similarly with peppermint. Whilst the oil is eminently suited to the treatment of respiratory conditions as an inhalant, due in particular to its antispasmodic and antiseptic actions, for the longer-term treatment of digestive disorders it is better to use extracts from the whole herb, where the action of the volatile oil is supported by the presence of bitters and tannins. In addition, in herbal medicine, the effect of one herb is usually supported and backed up by combining it with others.

Neither is it correct to assume that the essential oil is always the most active or therapeutically useful part of a plant. For example, although meadowsweet contains an essential oil outstanding in its antiseptic strength (according to Cavel,8 3.3cc of meadowsweet essence renders infertile 1000cc of microbic cultures in sewage, compared to 5.6cc of phenol per 1000cc), it also possesses several other valuable components, notably salicylic glycosides which are characterized by their excellent pain-relieving and anti-inflammatory qualities. Indeed, the familiar drug aspirin, being derived from salicylic acid, is named after this herb, its old country name being ‘spiraea’.

The kernels of the (bitter and sweet) almond tree are used to produce a fixed oil commonly known as sweet almond oil, which has a great many cosmetic uses. The kernels from the bitter almond tree, which are used to produce the essential oil which gives marzipan its characteristic taste, also contain cyanide, the well-known poison, in its unrefined form. This shows that there can be a great difference in the properties of a plant, even the same part of a plant, depending upon how it has been prepared.

Therapeutic Guidelines

As a general rule which is in line with the present-day aromatherapy ‘code of practice’, it is best to use essential oils as external remedies only. This is mainly due to the high concentration of the oils and the potential irritation or damage that they can cause to the mucous membranes and delicate stomach lining in undiluted form. There even seems to be some kind of natural order in this scheme, in that volatile oils mix readily with oils and ointments suited to external application, which are absorbed readily through the skin and vaporize easily for inhalation. When inhaled, they can affect an individual’s mood or feelings, and at the same time cause physiological changes in the body. Indeed, in a Japanese experiment carried out in 1963, it was found that the effects of essential oils on the digestive system were likely to be stronger if they were inhaled than if they were ingested. Herbs, on the other hand, yield up many of their qualities to water and alcohol which are appropriate for internal use but, lacking the concentrated aromatic element, they do not have the same subtle effects on the mind and emotions.

These are only superficial guidelines, for there are always exceptions to the rule. Plantain, for example, is an excellent wound-healing herb valuable for external use, although it does not contain any essential oil. Nor can we ignore the fact that a great many aromatic oils are used for flavouring our food and beverages and are consumed daily in minute amounts. Peppermint oil, for example, is used in a wide variety of alcoholic and non-alcoholic beverages, confectionery and prepared savoury foods, although the highest average use does not exceed 0.104 per cent. The mint oils, which include spearmint and cornmint, are also used extensively by the pharmaceutical and cosmetic industries in products such as toothpaste, cough and cold remedies, and as fragrance components in soaps, creams, lotions, as well as colognes and perfumes. In addition, cornmint is frequently used as the starting material for the production of ‘menthol’ for use in the drug industry.

It can be seen that the use of essential oils covers a wide and varied spectrum. On the one hand they share the holistic qualities of natural plant remedies, although it is true that some herbalists view essential oils in much the same light as they regard synthetic drugs, being a ‘part’ of the whole, rather than the entire herb. On the other hand, they play an active role in the modern pharmaceutical industry, either in their entirety or in the form of isolated constituents such as ‘phenol’ or ‘menthol’.

It is not the aim of this book to glorify natural remedies (some of which are in fact highly toxic) at the expense of scientific progress, nor to uphold the principles of our present-day drug-orientated culture, but simply to provide information about the oils themselves in their multifaceted nature.

Safety Precautions

Safety Data: Always check with specific SAFETY DATA before using a new oil, especially with regard to toxicity levels, phototoxicity, dermal irritation and sensitization.

Contra-Indications: Take note of any contra-indications when using particular oils. For example, fennel, hyssop and sage should be avoided by epileptics; clary sage should not be used while drinking alcohol; hops should not be used by anyone suffering from depression.

High Blood Pressure: Avoid the following oils in cases of high blood pressure: hyssop, rosemary, sage (all types) and thyme.

Homoeopathy: Homoeopathic treatment is not compatible with the following oils: black pepper, camphor, eucalyptus and the mint oils.

Pregnancy: During pregnancy use essential oils in half the usual stated amount. Take note of those oils which are contra-indicated in pregnancy.

Babies And Children: Use with care, in accordance with age.

 Babies (0–12 months) – use 1 drop of lavender, rose, chamomile or mandarin diluted in 1 tsp base oil for massage or bathing.

 Infants (1–5 years) – use 2–3 drops of ‘safe’ essential oils (non-toxic and non irritant to the skin), diluted in 1 tsp base oil for massage or bathing.

 Children (6–12 years) – use as for adults but in half the stated amount. Teenagers (over 12 years) – use as directed for adults.

3. THE BODY – ACTIONS AND APPLICATIONS

How Essential Oils Work

The therapeutic potential of essential oils, like other plant-derived remedies, has yet to be fully realized. Although numerous medical herbs have been utilized since antiquity, many of which have been exploited to provide the biologically active compounds which form the basis for most of our modern drugs (such as quinine and cocaine), there is still a great deal to be learnt about their precise pharmacology. This is particularly true of aromatic oils, which by their very nature have such a concentrated yet multifaceted make up. In addition, ‘only a small proportion of the world flora has been examined for pharmacologically active compounds, but with the ever-increasing danger of plants becoming extinct, there is a real risk that many important plant sources may be lost’.9

Modern research has largely confirmed the traditionally held beliefs regarding the therapeutic uses of particular plants, although with time the terminology has changed. A herb such as basil, at one time described as a ‘protection against evil’, or ‘good for the heart’ whose scent ‘taketh away sorrowfulness’, may in modern usage be described as an excellent prophylactic, nerve tonic and antidepressant. Like herbal remedies, an essential oil can cover a wide field of activities; indeed the same herb or oil (such as Melissa) can stimulate certain systems of the body while sedating or relaxing others. In order to gain a clearer understanding of the way essential oils work, and some of their particular areas of activity, it may be helpful to take an overall view of the systems of the human body.

The Skin

Skin problems are often the surface manifestation of a deeper condition, such as a build-up of toxins in the blood, hormonal imbalance or nervous and emotional difficulties. In this area the versatility of essential oils is particularly valuable because they are able to combat such complaints on a variety of levels. Since essential oils are soluble in oil and alcohol and impart their scent to water, they provide the ideal ingredient for cosmetics and general skin care as well as for the treatment of specific diseases.

Within this context the following activities are of particular benefit:

 Antiseptics for cuts, insect bites, spots, etc; for example, thyme, sage, eucalyptus, tea tree, clove, lavender and lemon.

 Anti-inflammatory oils for eczema, infected wounds, bumps, bruises, etc; for example, German and Roman chamomile, lavender and yarrow.

 Fungicidal oils for athlete’s foot, candida, ringworm, etc; for example, lavender, tea tree, myrrh, patchouli and sweet marjoram.

 Granulation stimulating or cicatrizing (healing) agents for burns, cuts, scars, stretch marks, etc; for example, lavender, chamomile, rose, neroli, frankincense and geranium.