Understanding Essential Oils
Many of the aromatic compounds of plants are from classes of compounds that are volatile — they quickly dissipate into the air, even at room temperature. Many boil at 180 to 240 degrees Fahrenheit and are carried off in the steam that's created when the herbs are simmered in water. This means that much of the healing essence of certain plants — peppermint, for example — is lost when you simmer them in an uncovered pot.
Essential oils or volatile oils are the most important group of chemical molecules of plants that make smells what they are. The origin of these names comes from the word "essence," because the fragrances are the essence of many plants, and "volatile" because of their volatility. Volatile oils contain one or two hundred different carbon- and hydrogen-based compounds called terpenes or hydrocarbons. Each volatile oil is made up of a unique blend of up to one hundred different terpenes, which like an artist's palette, gives the plant the ability to build unique essential oils each with their biological activity and mood- and emotion-affecting properties. Essential oils aren't true oils like almond oil, olive oil, or flaxseed oil — those are called fixed oils. Fixed oils don't vaporize the way essential oils do, and they are much heavier.
Essential oils are super-concentrated. For example, it takes about 16 pounds of fresh peppermint leaves to produce an ounce of essential oil. These oils constitute important active ingredients and flavor additives in many kinds of familiar, everyday products — candies, syrups, toothpastes, mouthwashes, cleaning products, skin creams, lip balms, shampoos, bath salts, and soaps. Essential oils even give flavor and aroma to the spices that you use to add zest to your cooking, such as cinnamon, allspice, and nutmeg used for apple cider, pies, and baked goods. Nutmeg, allspice, thyme, oregano, basil, and savory all contain essential oils.
They smell good, and they add zest to foods, but essential oils have many therapeutic effects you can put to work in many situations. For instance, if you have a stomachache from indulging in a rich dessert, simply add 2 drops of peppermint oil to a cup of hot water and experience fast relief. Here's more about how the healing powers of essential oils work.
- The essential oils of plants are biologically active when the airborne molecules are inhaled, stimulating olfactory nerves which in turn stimulate centers of the brain. The molecules may stimulate an immune response after entering the bronchial area and lungs, helping your body fight an infection. When you inhale essential oils, from the steam from a simmering pot of eucalyptus leaves for example, you can help your body dry up mucus secretions, lower inflammation, shrink swollen sinus membranes, and enhance airflow. All of these effects can help you breathe more freely during a cold or hay fever attack.
- Try diluting a little essential oil, such as lavender (one-fourth teaspoon), with a fixed oil like sweet almond oil (six tablespoons) and rub it on the skin. You may notice an immediate boost in your mood. The individual components of the essential oil penetrate the skin and the blood vessels, relieving pain and swelling, stimulating blood flow, and bringing healing to the area, or may enter the blood, ultimately affecting the brain, nervous system, and organs.
- Many essential oils are antiseptic and are among nature's most powerful protectors against bacteria and other infectious organisms. Thyme oil contains a chemical called thymol that is murder on bacteria and fungus. The compound is included in commercial soaps and antiseptics.
- Certain essential oils are toxic and a few are highly toxic when they're taken internally in amounts over a few drops. This amount varies, but as little as one-half ounce of pennyroyal oil has caused death. When used in products for external use and applied to the area undiluted, toxic essential oils are unlikely to cause a major problem, although they may cause redness and irritation of your skin. Be aware of the following seven toxic oils — use them more cautiously or under the guidance of a qualified herbalist or aromatherapist (and never take them internally).
Pennyroyal: An infusion of the leaves makes a safe digestive tea, but the essential oil has killed women who took it internally in an attempt to abort a fetus.
Calamus: European calamus oil contains a cancer-causing terpene called thujone that is toxic to the nervous system. American calamus is free of it and is safe, but identity of any calamus oil isn't certain. Avoid using any calamus oil internally.
Wormwood: Wormwood oil is the active ingredient of the infamous mind-altering drink (called absinthe) that was favored by artists at the end of the nineteenth century. It contains thujone. Don't use wormwood or mugwort (a related plant) tincture or essential oil internally without the advice of a qualified herbalist.
Tansy: Tansy contains thujone. Another traditional abortifacient (used to induce abortions), tansy herb is toxic in all forms, including the tea. Tansy is a common pungent garden herb that looks a little like chrysanthemum and feverfew — both close relatives.
Wormseed: Used traditionally to kill intestinal worms, the oil is highly toxic and has caused deaths in children who were given too much.
Wintergreen: The fragrant oil contains a toxic terpene called methyl salicylate, which is from the same class of chemicals as aspirin. People often use wintergreen oil externally to help relieve the aches and pains of neuralgia and arthritis.
Camphor: This essential oil occurs in a semi-solid buttery state at room temperature (not as a liquid like most essential oils). Camphor is a single compound, a monoterpene, which is toxic to the nervous system, causing mental confusion, nausea, and vomiting when taken internally at a high enough dose. Camphor is commonly used externally in products to clear the nasal passages, open up the chest, stimulate circulation, and relieve pain — it's the key ingredient in Vicks Vapo Rub and provides its pungent smell.
- An alcohol-based preparation (such as a liquid extract or tincture) of a plant high in essential oils like eucalyptus or pennyroyal is much more potent than a tea made with water. This means that the teas made with these plants are extremely safe, but you need to be careful with the tinctures that contain the essential oil plants.