What are Essential Oils?

Essential Oils and How They Work

Essential oils are more than just highly concentrated plant extracts. Most possess potent medicinal qualities, and many are valued for their exceptional cosmetic qualities. While the whole plants or plant parts they are derived from possess beneficial qualities, essential oils are much more powerful.

Sometimes referred to as ethereal oils or volatile oils, essential oils carry the actual essence or fragrance of the plants from which they are extracted. A few popular essential oils are derived from whole plants, but most are derived from specific sections of the plants for which they are named. Some essential oils, including almond and nutmeg oils, come from seeds. Many, including patchouli, eucalyptus, and tea tree oils, are extracted from leaves. Still others come from wood, flowers, resin, or roots. Some plants, including cinnamon and bitter orange, are used as sources for more than one distinct type of essential oil.

Professional practitioners use approximately three hundred essential oils to treat a vast range of illnesses, but home practitioners typically use between ten and twenty essential oils on a regular basis. Some favorites include lavender, eucalyptus, clary sage, and orange essential oils.


Cave paintings discovered in Lascaux, France, suggest that prehistoric people used medicinal plants on a daily basis. These fascinating images have been carbon dated to approximately 18,000 BCE.

Humans have possessed an understanding of the healing power of plants for thousands of years. While it is not clear when essential oils were first distilled, we know that these oils were used in various cultures, and we know that they were used for religious ceremonies as well as for healing purposes.

Herbs and Essential Oils in Ancient Times

The Egyptian people are widely renowned for their achievements, so it might not come as a surprise that ancient Egyptians were among the first to use essential oils. In fact, records show that aromatic oils were part of daily life in Egypt as early as 4500 BCE. Cinnamon, myrrh, sandalwood, and frankincense were treasured favorites; they were of such great value that they were sometimes purchased with pure gold.

In Egypt, pure essential oils were believed to be sacred, and only high priests and royalty had the authority to use them; each deity was assigned a signature essential oil blend. Images and carvings of gods and goddesses were frequently anointed with precious oils during religious ceremonies. Each pharaoh used a variety of unique essential oil blends during meditation and intimacy, and even during preparation for war.

Around 3000 BCE, scholars in India developed the science of Ayurveda, which relies heavily on curative potions containing a wide variety of essential oils. Ancient Vedic literature lists more than seven hundred curative substances, including some of today’s favorites, such as ginger and cinnamon essential oils.

In China, aromatic herbs and essential oils made their way into remedies for a whole host of ailments. Many of these compounds are still used by today’s Eastern medicine practitioners. Chinese scholars first recorded the use of essential oils between 2697 and 2597 BCE, during Huang Ti’s reign, and the fabled Suwen, or Yellow Emperor’s Classic of Internal Medicine , remains a significant text today.

Essential oils are mentioned in both the New and Old Testaments of the Bible—over two hundred times. Some very popular biblical essential oils are cedarwood, cinnamon, fir, frankincense, myrrh, and spikenard. These oils were used for anointing, for religious purposes, and, it seems, for the pure enjoyment of their fragrances. They were also highly valued as gifts; in the story of the Magi, the precious gifts they brought to Jesus of Nazareth at his birth included frankincense and myrrh.

Greek and Roman ancients also used essential oils, mostly for aromatherapy, therapeutic massage, personal hygiene, and medicine. Essential oil of myrrh was blended into an ointment for battlefield use; it proved an effective remedy for preventing post-injury infections.

We know Hippocrates as the “Father of Medicine.” Between 500 and 400 BCE, he documented the medicinal effects of essential oils and elements from over three hundred plants, many of which are still popular today. Hippocrates taught his students that “a perfumed bath and a scented massage every day is the way to good health.” His wisdom continues to influence modern medicine in the form of the Hippocratic Oath taken by doctors.

Galen was an influential Greek medical practitioner. Born in 131 CE and educated in Alexandria and Smyrna, he gained fame during his tenure as the surgeon to the gladiators of Pergamos. Thanks to Galen’s vast knowledge of the effective use of essential oils and other medicines, no gladiator died of infection while under his care. Galen’s success led him to an assignment as personal physician to Roman Emperor Marcus Aurelius. He remained a part of the Emperor’s court for the rest of his life, which he spent composing a vast body of medical texts that included plants in various medicinal categories. Though Galen died around 201 CE, his work lives on in the form of Galenic medicine, which is still practiced in India and Pakistan.

Essential Oils, Aromatherapy, and the Dawn of Modern Medicine

When Rome fell, physicians fled, carrying books by Hippocrates and Galen with them. These books made their way into Persia, where they were translated into several languages for distribution to scholars. Ali ibn Sina, who was often referred to as Avicenna the Arab, was a child prodigy born in 980 CE. He was educated as a physician and is said to have begun practicing medicine at age twelve. Ibn Sina catalogued approximately eight hundred plants, describing their effects on the human body in detail. He’s also credited with refining and recording traditional distillation methods for extracting pure, high-quality essential oils from aromatic plants.

Europeans gained firsthand knowledge of essential oils and herbal medicines after crusading knights visited the Middle East. These knights and their armies began wearing and carrying perfumes, and many acquired knowledge of distillation techniques.

During the bubonic plague epidemic of the 1400s, desperate doctors decided to try Ayurvedic blends in place of ineffective medicines. These ancient remedies, which included essential oils of camphor, meadowsweet, rosemary, and lavender, proved to be effective. At the same time, frankincense and Scots pine were burned in the streets to ward off evil spirits. Fewer people died of the plague in areas where this practice was common.

Nicholas Culpeper’s 1653 book Complete Herbal offers detailed remedies for many medical conditions. These venerable tonics contain essential oils and other effective plant-based compounds that are still widely used today.

The powerful therapeutic properties of essential oils were rediscovered in 1910, when French chemist René-Maurice Gattefossé badly burned his hands in a laboratory explosion and gangrene quickly developed. Gattefossé subsequently treated his hands with a single application of lavender oil, and healing began swiftly. Following this incident, Gattefossé and a colleague conducted further research on the healing properties of lavender essential oil before introducing it to French hospitals.

Later, Parisian doctor Jean Valnet used therapeutic-grade essential oils to treat injured soldiers during World War II. Two of Valnet’s students, Dr. Paul Belaiche and Dr. Jean-Claude Lapraz, conducted extensive research, examining essential oils for their antiviral, antibacterial, antifungal, and antiseptic properties. They concluded that these powerful natural substances have substantial healing capabilities.

The using of aromatherapy and essential oils in North America is a fascinating one. We know that Native Americans relied heavily upon nature’s pharmacy, utilizing plants to increase well-being in a variety of ways. Echinacea, which is used today in a variety of forms, including whole herb and essential oil, was a favorite treatment for headaches, including painful migraines. Skunk cabbage was used to treat nervous disorders, horsemint was applied to ease back pain, and wild cherry was used to treat coughs. White pine, which Native Americans used for treating colds, remains a popular aromatherapy cold treatment today. If you’ve ever used arnica to help bruises, you are using a well-known Native American remedy.

When European settlers came to North America, they brought favorite European herbs with them. At first, these precious plants were their only source of medicine, and the plants were also used to make food more palatable. Pennyroyal and wormwood were useful for controlling fleas and other insects. Later records show that in 1631, John Winthrop, Jr. of Suffolk ordered a vast amount of seeds to be taken to America’s Massachusetts Bay Colony. Among the forty-eight plant species he ordered at a cost of £160, which was a fortune in those days, were rosemary, clary sage, angelica root, hyssop, catnip, and lovage—all of which are available as essential oils today.

As it turns out, the ancients and those who followed the pathways they laid were right. Many bacteria, fungi, and viruses die when placed in contact with certain essential oils, particularly when those oils contain terpenes, thymol, carvacrol, and phenols. Essential oils and chemical reproductions of their active ingredients are widely used in compounding modern pharmaceuticals. Extensive studies and clinical investigations are ongoing, and thanks to modern technology, many of today’s medical professionals incorporate remedies containing essential oils into holistic practice.


Every essential oil contains approximately one hundred different components, each of which acts on the body in different ways. Aromatic chemicals derived from phenylpropane are the precursors of the amino acids that connect with one another to form nearly all the body’s structures.

Complex Natural Substances

On a chemical level, our bodies and essential oils are made from many of the same substances, including complex chemicals called terpineols, which are naturally occurring alcohols that play a vital role in the body’s production of vitamins, energy, and hormones. They are produced during the constant process of cellular respiration, and they contribute to the body’s cellular energy supply, aiding in processes such as metabolism and healing. These important chemicals are also found in many essential oils, as plants produce them during growth. They are very easy for the human body to absorb and use for both nourishment and healing.

Despite their complexity, these oils are for the most part noninvasive and nontoxic, though there are a select few derived from deadly nightshades, which should be used only with extreme care. Belladonna is among the most toxic of all essential oils. Although it has a long history of benign use, including in cosmetics and medicines and as a surgical anesthetic, it has also been used as a deadly poison. Wolfsbane, which is also known as monkshood, is another deadly essential oil derived from a plant so poisonous that growers must avoid skin contact.

Before being crowned as king in 1040, Macbeth is said to have used nightshade to poison Danish invaders who landed on Scotland’s shore. They demanded mead, which Macbeth laced with belladonna. Once the invaders had fallen into a stupor, Macbeth and his followers slaughtered them all.

Each of the body’s cells contains electrons, which carry an electric charge and are affected by other sources of electricity. A number of medical treatments use electricity: think of the way a defibrillator can be used to restart the heart following cardiac arrest, and consider how electrotherapy is used in many beneficial ways, including stimulating the brain, helping injured muscles to heal, and improving blood flow.

Polarization is a process that separates positive and negative electrical charges within any object or energy form, including the body’s cells and light. When light is polarized, its vibrations often occur in circular ellipses that can be used to promote healing within the body’s tissues. Polarized light therapy is used in a number of medical applications, ranging from cosmetic procedures and treating skin disorders to providing relief from pain, speeding burn healing, treating ulcerated skin, and penetrating deep into joints to relieve pain.

Essential oils possess some of the same rotational properties as polarized light. Called dextrorotation and levorotation, these characteristics have a marked effect on the body’s electromagnetic field. Researchers theorize that these properties contribute to the body’s ability to heal itself in much the same way electric charges do.

In addition, essential oils have a profoundly positive effect on blood circulation. They can play an important role in carrying oxygen and vital nutrients to the body’s tissues while aiding in the efficient disposal of the waste normal metabolism processes leave behind. By increasing blood flow, essential oils improve immune system efficiency and decrease blood viscosity, which in turn benefits the entire body, including the brain.

Though sweet-smelling and often used simply because their fragrances are so delightful, essential oils actually contain the most powerful chemicals plants are capable of synthesizing from the sun, the water, and the soil that nourishes them. Their molecular structures are incredibly complex and powerful, yet essential oils are easy and pleasurable to use.

While each essential oil is valuable on its own, they may be combined to form even stronger chemical compounds whose synergistic effects far surpass those of single oils. In contrast, very powerful oils and blends may be diluted to provide the correct dosage.

The Healing Power of Essential Oils

Many essential oils act as adaptogens, which are natural balancers. Adaptogens promote a balancing reaction in the body, which in turn can affect a multitude of the body’s systems, including blood pressure, the autonomic nervous system, the endocrine system, and digestion.

Many essential oils are natural analgesics—substances that provide relief from pain by acting on the peripheral and ventral nervous systems. For instance, wintergreen essential oil contains between 85 and 99 percent methyl salicylate, which is the same active ingredient contained in aspirin. Before synthetic pain relievers were introduced in the 1920s, wintergreen and birch were considered to be the best remedies for pain; in fact, Native Americans used both plants before written records were ever kept.

Pain is characterized by a state of mental, emotional, or physical lack of well-being. While modern pharmaceuticals play an important role in managing pain, most of these drugs lack the power analgesic essential oils possess in that they often address physical pain only. Wintergreen essential oil is also known to bring about feelings of self-acceptance, and peppermint essential oil, which has been shown effective in blocking pain, is also renowned for its ability to promote an overall feeling of calm and well-being.

Doctors have battled against infections since the beginning of time, and some of the best tools in their arsenal are antiseptics, which are antimicrobial substances that reduce the potential for infection when applied to living tissues. Some antiseptics are also classified as germicides for their ability to destroy microbes, and others are antibacterial and inhibit microbial growth. Although most antiseptics manufactured today contain a variety of chemicals, antiseptic essential oils are completely natural. Some of the most powerful antiseptic essential oils include lavender oil, tea tree oil, and clove oil. There are many different ways to blend antiseptic essential oils to improve efficacy, and there are a variety of methods for using them, including infusing them in bathwater, applying them to minor wounds, or adding them to poultices or compresses.

Clove essential oil is so effective as an anti-inflammatory and analgesic that it has been approved for use as a dental anesthetic by the American Dental Association. It is excellent when included in mouthwash recipes, particularly if you suffer from sore, inflamed gums.

Inflammation is part of the body’s defense system. This valuable immune response helps eliminate negative stimuli so the body’s structures can begin to heal after an injury or following exposure to a harmful substance. When tissues become inflamed, redness, swelling, or pain can occur. When these symptoms last only for a short time, they are typically not harmful. When inflammation symptoms become chronic, they can begin to cause damage to the very same structures they are designed to protect. That’s when minimizing inflammation becomes vital to continued health and well-being.

Many essential oils have anti-inflammatory properties. For example, thyme essential oil is a useful ingredient in blends designed to reduce muscle fatigue, while pure, unadulterated rose otto oil is effective in treating dry or inflamed skin and even in diminishing the appearance of broken capillaries.

Whether you are suffering from a skin condition, muscle soreness, chronic migraines, or other painful or irritating bodily conditions, there is a great likelihood that one or more of the many essential oils available will prove to be effective in alleviating your symptoms.

In addition to their therapeutic benefits, essential oils have many practical applications. For example, they can be used to create natural laundry detergents and nontoxic household cleaners. Some, such as citronella, make effective natural insect repellents. If you’re looking for a way to reduce the amount of chemicals you use in your home, making your own products with essential oils is an excellent choice.


Aromatherapy is a form of alternative medicine in which essential oils are used to positively influence a person’s mind, bodily health, mood, or cognitive function. Though essential oils are at the heart of aromatherapy, complementary natural ingredients such as jojoba, herbs, hydrosols, mineral clays, and other substances are used as well.

Keep in mind that many items claiming to be aromatherapy products—including scented candles, perfume oils, and fragrance oils—actually contain synthetic ingredients. For any substance to be aromatherapeutic, it must be completely natural. Products with labeling such as “made with natural ingredients” or “made with essential oils” typically contain only small amounts of natural ingredients or essential oils, which is one reason many people choose to purchase their own essential oils and blend customized aromatherapy products at home.

During the Dark Ages, aromatherapy was considered akin to witchcraft, and aromatherapy practitioners were forced underground. The Catholic church banned many natural remedies, because believers viewed illness as a punishment from God. Followers were instructed to pray and bleed themselves in hopes of obtaining a cure.

The Science of Scent

The human sense of smell is about ten thousand times more powerful than other senses, and scent travels to the brain so rapidly that the mental or physical response to the fragrance an essential oil emits can be immediate. When you inhale an essential oil, its scent travels first through olfactory nerve cells inside the nose and into the larger olfactory system. The olfactory system then delivers the aroma to the olfactory bulb located inside the brain’s limbic system, which serves as the seat of emotions and the originator of emotional behavior.

Depending upon which essential oil you are inhaling, you may feel a rapid release of mental strain or negative emotions, and you may feel muscle tension ease at the same time. You may feel more alert, excited, or engaged with your surroundings, and if the scent you are inhaling is a familiar one, you may rapidly access your collective unconscious and experience strong memories, particularly when those memories are closely associated with deeply emotional feelings.

The limbic system is, in turn, connected to the pituitary gland and the hypothalamus, which controls the release of hormones that affect one’s nervous system, appetite, body temperature, concentration, and stress levels. Essential oils interact with the limbic system by providing input that activates the hypothalamus, instructing it to release neurochemicals to calm, relax, or stimulate the body. This is why aromatherapy can play such an important part in stress reduction, appetite control, increasing alertness, and much more. Whether essential oils are deeply inhaled or applied to the skin, the odor molecules travel straight to the appropriate limbic destination, where neurochemicals instruct the body to respond as desired.

Our individual senses of smell are a lot like fingerprints. Everyone smells different odors in a unique way, with the exception of identical twins, who have identical odor receptors and who process scents in exactly the same way. An essential oil that smells fantastic to one person may seem less than appealing to another.

Benefits of Aromatherapy

Many people find that aromatherapy helps bring about feelings of spiritual well-being. Frankincense is a classic example of an essential oil that has been used for centuries to add fragrance to sacred spaces such as churches, sanctuaries, and home meditation rooms. Diffusing frankincense and then taking long, slow breaths can help you focus as you embark upon any spiritual journey.

Essential oils have wonderfully positive effects on every level, with unique properties that enhance the body, mind, and spirit. Aromatherapy, when understood this way, is more than just the scientific application of essential oils to bring about beneficial changes in the physical realm; it is the creative use of essential oils to evoke positive changes on aesthetic and mystical levels as well.
Essential Oils and How They Work