Essential oils: What are Essential Oils?

Essential oils are aromatic volatile oils that come from plants or plant parts.

The use of highly concentrated aromatic essential oils for healing is often called aromatherapy. While the term aromatherapy is relatively new, the use of fragrant plant oils as medicines, perfumes, and cosmetics is ancient. People in the Middle East devised distillation methods to extract essential oils from plants as early as 1000 BCE. By the Middle Ages, many people throughout Europe used essential oils as perfumes and medicines.

Plants produce essential oils, also called volatile oils, in specialized oil glands located within or on their leaves, flowers, roots, fruit, seeds, or other parts. Long important in commercial perfumery, these oils are still used to create exquisite and expensive perfumes, but they have many other uses, too. Commercial food and beverage makers use essential oils as flavorings. Other industries incorporate essential oils with antiseptic properties into products designed to kill germs. Essential oil of thyme, for example, is a main ingredient in some mouthwashes. Pure plant essential oils are popular in the manufacture of natural cosmetics because they have properties, including anti-inflammatory and antiseptic abilities, that help soothe and rejuvenate your skin.

Essential Oils

Scientific research has shown that aromas can have a profound effect on human emotions, and plant essential oils (aromatherapy) are often used to improve mood or state of mind. Some plant oils, such as peppermint, have uplifting and invigorating effects, helping to refresh and clear the mind. Others, like lavender, are calming and can help induce relaxation or even sleep. A growing body of research supports the clinical use of aromatherapy to treat certain conditions, such as anxiety. One small clinical study, for example, showed that massage with lavender essential oil reduced patient anxiety in a hospital intensive care unit. Other clinical studies have confirmed the traditional use of lavender essential oil to treat insomnia. Hundreds of laboratory studies have documented the antiseptic and anti-inflammatory properties of other essential oils.

How Essential Oils Work

Essential oils are composed of molecules of aromatic compounds. One essential oil might contain hundreds of these aromatic compounds, which contribute to the oil’s unique aroma and physiological actions. Chemists call these “volatile compounds” because their molecules easily evaporate, or volatilize, into the air. This is contrasted with fixed oils, such as cooking oils, which do not evaporate as quickly.

Essential oils can enter your body via absorption through your skin. In addition, the aromatic molecules floating around in the air enter your nose and are picked up by olfactory receptors. These transport information to the olfactory bulb located at the top of the nasal passage at the base of your brain. From there, scent information is passed on to the limbic system, a primitive part of your brain responsible for very basic body functions. The limbic system communicates with the hypothalamus and pituitary, master glands that affect and regulate fundamental body processes including the secretion of hormones and the regulation of moods, digestion, appetite, sexual arousal, and heartbeat. Aromas also stimulate the parts of your brain that control memory.

Important Cautions

Essential oils are extremely concentrated and must be treated with respect. A good rule of thumb is that more is not better! Never use undiluted essential oils directly on your skin — always use them in a diluted form (in a carrier oil, cream, or water), or vaporize them and gently inhale them. Never take essential oils internally, and keep them away from your eyes. Be sure to use only high-grade, pure plant essential oils (not synthetic fragrance oils), and become educated on the use of essential oils by reading a reputable book devoted to the subject or consulting a trained aromatherapy professional.

Essential oils are estimated to be about 50 times stronger than the whole herbs from which they are extracted, but the concentration depends on the species from which they are derived. Also, be aware that some herbs that are perfectly safe to eat or to drink as a tea contain very strong, potentially toxic essential oils that must be used with caution. Examples include cinnamon bark (Cinnamomum verum), clove (Syzygium aromaticum), oregano (Origanum vulgare), savory (Satureja spp.), and thyme (Thymus vulgaris). Other essential oils, such as tansy (Tanacetum vulgare), are so toxic that they should not be used at all in aromatherapy. Essential oils made from flowers (such as rose or orange blossom) generally are the mildest essential oils.

Using Essential Oils

Using Essential Oils

Two of the most popular ways to use essential oils are by inhaling them (smelling them) and by applying them to the skin (in a massage oil or facial oil). To obtain the benefits of aromatherapy, essential oils can also be added to bathwater, skin creams, and lotions; used to scent bedding, clothing, and laundry; and incorporated into homemade air-fresheners. A diffuser (a device specially designed to disperse essential oils into the air) can be used to fill an entire room with fragrance.

Inhaling essential oils: Add a few drops of essential oil to a piece of cloth or a cotton ball. To make a steam inhalation, add three to five drops of essential oil to a pot of steaming water. Steam provides a vehicle not only for inhaling essential oils, but also for carrying the essential oils to your skin. Position your face about 12 inches over the steaming water, drape a towel over your head, and breathe the steam for a moment or two. Remove the towel and take a few breaths of fresh air. Repeat the process for a maximum of 5 to 10 minutes.

Applying essential oils to your skin: To protect your skin from irritation, always dilute essential oils in a carrier oil (a vegetable or nut oil) such as sweet almond, grapeseed, sunflower, olive, jojoba, apricot kernel, kukui nut, or hazelnut oil.

Aromatic waters are another easy and pleasant way to use essential oils on your skin. To make aromatic water, add 10 drops of essential oil to 1 ounce of water in a spray bottle. To use, thoroughly shake the mixture, then mist your body and face, being sure to close your eyes before you spray.


Essential oils are highly concentrated sources of plant compounds. Many of them have healing properties, but they should never be taken internally.

Carrot seed (Daucus carota) Stimulates and regenerates skin cells; good for dry and mature skin
Chamomile, German (Matricaria recutita) Anti-inflammatory; soothes sensitive skin and sore muscles; relaxing, uplifting aroma; might help ease insomnia
Clary sage (Salvia sclarea) Eases muscle tension and menstrual cramps; helpful for oily skin; relaxing, euphoric aroma
Eucalyptus (Eucalyptus globulus) Antibacterial, decongestant; clears sinuses and bronchial tubes; stimulating aroma
Geranium (Pelargonium graveolens) Anti-inflammatory, antibacterial, antifungal; stimulates and regenerates skin cells; helpful for mature skin; relaxing aroma
Lavender (Lavandula angustifolia) Anti-inflammatory, antibacterial, antifungal; general first aid; stimulates and regenerates skin cells; helpful for sensitive and mature skin; calming and relaxing, might help ease insomnia
Lemon (limon) Antibacterial, antifungal; helpful for oily skin; uplifting aroma; might help ease stress and insomnia
Peppermint (Mentha × piperita) Antibacterial; uplifting, stimulating aroma
Rose (Rosa × centifolia or R. × damascena) Antiseptic, anti-inflammatory; stimulates and regenerates skin cells; helpful for mature skin
Rosemary (Rosmarinus officinalis) Soothes muscle aches; stimulates circulation; helpful for mature skin; stimulating aroma
Tea tree (Melaleuca alternifolia) Antibacterial, antifungal, anti-inflammatory

How Essential Oils Are Produced

All plant aromas can be attributed to the presence of essential oils, which perform vital functions in the life cycles of plants. Some aromas produced by essential oils serve to attract pollinators. Some aromas repel pests or discourage grazing animals from eating the plant. Others protect plants against infection by bacteria, viruses, and fungi.

For commercial use, huge amounts of plant material are needed to produce small quantities of essential oils, which explains why some essential oils are so costly to buy. For example, 3 to 6 pounds of eucalyptus leaves are used to make 1 ounce of its essential oil. Ten to 20 pounds of lavender flowers are used to make 1 ounce of its essential oil. Production of 1 ounce of jasmine oil requires 160 to 280 pounds of flowers. And 2,000 rose petals are needed to make a single drop of rose oil.

Several different techniques can be used to extract essential oil, depending on the plant.

Steam distillation: Approximately 80 percent of plant essential oils are obtained by steam distillation — a process that uses steam, heat, and condensation to separate a plant’s essential oils from its solid and water components. This technology uses no solvents, so the product is very pure. Essential oils produced this way include lavender, rose-mary, peppermint, and eucalyptus.

Solvent extraction: For very delicate plants easily damaged by heat, other extraction techniques are available. Solvent extraction uses liquid solvents to dissolve and extract essential oils from the plant; the solvent is then evaporated under pressure. The initial product, called a concrete, is a sticky substance that contains plant waxes and pigments in addition to essential oils. The concrete can be sold as is or further refined to create a product called an absolute. This process is expensive, so it’s generally used only to extract desirable and costly fragrances (like jasmine) that can’t be produced through distillation. Solvent-extracted concretes and absolutes can contain traces of the solvents used to make them, so they aren’t appropriate for therapeutic use but are fine to use as perfumes.

Supercritical carbon dioxide (CO2) extraction: This newer technology uses carbon dioxide gas under low heat conditions to extract essential oils. Because less heat is used, the aroma of the essential oil is very close to that of the original plant. The final product is also free of solvent residues and is considered very pure. But the equipment needed for CO2 extraction is expensive, as are the oils produced.

Two types of essential oils are produced through CO2 extraction, using slightly different technologies. One, called a selective extract, is a liquid composed mainly of volatile compounds. Oils produced this way include frankincense and myrrh. The other type, called a total extract, contains volatile components as well as fats, waxes, and pigments with medicinal properties. This technology is used to produce essential oil extracts of carrot seed, calendula, chamomile, and vanilla. It’s also used to manufacture high-quality herbal extracts.

Cold expression: The essential oils of citrus fruits such as lemons, grapefruits, oranges, and limes are found in special oil glands in the rinds of these fruits. These oils are often extracted through a process called cold expression, which involves crushing the rinds to press out the oil, much like the way olive oil is produced. Citrus oils can also be produced through distillation.

Enfleurage: The oldest method for producing essential oils, rarely used today, is called enfleurage. The procedure involves placing fragrant blossoms on solid sheets of animal or vegetable fat and allowing the scent of the flowers to permeate the oil. When the fragrances in the blossoms are exhausted — having been absorbed by the fat — they are removed and replaced with fresh flowers. This process is repeated until the fat is saturated with volatile oils. A solvent can be used to extract the oils from the fat, or the fat can be used as is, in the form of an enfleurage pomade. Before the advent of solvent extraction, enfleurage was the only method available for extracting essential oils from delicate flowers such as rose, jasmine, and tuberose. This is a very old system of extraction that traces its origins to ancient Egypt, where fragrant flowers were extracted in animal fat and used to perfume the body.

Hydrosols: Hydrosols — true “flower waters” — are by-products of the steam distillation of essential oils. A hydrosol is the water component left behind when a plant’s essential oil is separated out in the distillation process. Hydrosols contain water-soluble compounds that make them fragrant and soothing to the skin.

Two of the best-known and most popular hydrosols are orange flower water and rose water. Both have traditionally been used in cosmetics and for culinary flavorings. Hydrosols also make refreshing, aromatic body mists and skin toners, and these are sold in spray bottles. Some commercially available hydrosols include lavender, geranium, chamomile, rose, neroli (or orange blossom), and rosemary. When purchasing a hydrosol, look carefully at the label to be sure it is a true hydrosol and not aromatic water, which is a blend of water and essential oils.


Essential oils are extremely concentrated. You can benefit from just a few drops diluted in water or a carrier oil, lotion, or cream. Good carrier oils include sweet almond, grapeseed, and olive oils.

Aromatic water (body mist) 10 drops per 1 oz water
Bathwater 3–6 drops per tub
Body or facial oil 6–8 drops per 1 oz carrier oil
Footbath 5 drops per basin of water
Massage oil 6–8 drops per 1 oz carrier oil
Room spray 15–20 drops per 1 oz water
Skin cream or lotion 6–8 drops per 1 oz lotion or cream
Steam inhalation 3–5 drops per 1 quart steaming water

Ylang-ylang - the aroma of this herb’s essential oil can vary from floral to fruity.

Intensely fragrant ylang-ylang blossoms are frequently used to scent perfumes, soaps, and candles. The aroma of this herb’s oil can vary from floral to fruity.

How to Make Natural Perfumes

Using essential oils to create original fragrance blends for homemade cosmetics, air fresheners, or perfumes is fun and easy. And by making your own formulas you can avoid the harmful chemical compounds, such as phthalates, commonly used in commercial perfumes and beauty-care products. (Recent research has linked phthalates to serious health conditions.)

Start by choosing one essential oil to serve as the backbone of the fragrance, and then add small amounts of other oils, sniffing to judge the effect after each addition. You could use a fixative, such as glycerin, to help slow the evaporation rate of the essential oils. But before you add a fixative to any fragrance, test it on a small area of your skin, as it could cause an allergic reaction. Pay attention to the intensity of each oil, and use extremely strong-smelling oils sparingly so their presence does not overwhelm the others. A good rule of thumb is to use only one drop of very strong-smelling oil — such as jasmine, patchouli, rosemary, or ylang-ylang — for every 5 to 10 drops of milder-smelling oil, such as citrus or lavender.

Make small batches of fragrance until the process becomes comfortable. Take notes so that you can duplicate your favorites later. To make a perfume, add about 12 drops of a blend to 1 ounce of a carrier oil. (Jojoba oil makes a good perfume base.)