Understanding Essential Oils

Many of the aromatic compound of plants are volatile - that is they quickly dissipate into the air, even at room temperature. Essential oils or volatile oils are the most important group of chemicals from plants that make the smells (or aromas) what they are.

The word 'essential' is used because the fragrance is the essence of many plants and 'volatile' simply describes their volatility. Each volatile oil is made up of up to 100 different components which 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 - these are called fixed oils. Fixed oils don't vaporise the way essential oils do, and they are much heavier.

Essential oils are super concentrated. For example it takes about 16 lbs of fresh peppermint leaves to produce an ounce of essential oil. These oils constitute important and active ingredients and flavour additives. They also give the flavour and aroma to the spices that add zest to cooking. The essential oils also have therapeutic effects you can put to work in many different situations.

The essential oils are biologically active when the air molecules are inhaled, stimulating our sense of smell (olfactory) nerves which in turn stimulate centres in the brain. The molecules may stimulate an immune response after entering the bronchial area and lungs, helping your body to fight infection.

For example, when you inhale the eucalyptus essential oil (from the steam of a simmering pot of eucalyptus leaves) you can help your body dry up mucus secretions, lower inflammation, shrink swollen sinus membranes and enhance airflow. All of these can assist you to breath more easily when you have a cold or hay fever attack.

Try diluting a little essential oil such as lavender (1/4 teaspoon) with a fixed oil such as almond oil (6 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, 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 natures most powerful protectors against bacteria and other infectious organisms.

Certain essential oils are toxic and a few are highly toxic when they are taken internally in amounts over a few drops. When used in products for external use and applied to the area undiluted they are unlikely to cause a major problem although they can cause redness and irritation to the skin.

An alcohol based preparation (such as a liquid extract or tincture) of a plant high in essential oils such as 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 more careful with the tinctures.


Using essential oils safely

Many essential oils like orange or peppermint are mild and have a low toxic potential even when used internally.

When used externally straight on the skin, some essential oils like thyme and sage may cause redness and irritation.

Using products that contain small amounts of essential oils isn't a problem for most people, but allergic reactions or skin sensitivity are possible. Use a small amount of essential oils on a small patch of skin overnight. If redness or irritation doesn't occur by then, you're unlikely to have a problem when you use the product. Additional safety precautions are as follows:

  • read and follow all label cautions and warnings,
  • keep out of reach of children and pets,
  • do not use on babies, young children or pets,
  • keep away from flame, heat and ignition sources (essential oils are flammable),
  • do not apply undiluted (neat) essential oils directly onto skin - dilute with a carrier oil,
  • keep essential oils out of eyes, ears, nose, mouth and any body opening,
  • never assume an essential oil possesses the same properties as its plant,
  • if you have sensitive skin, epilepsy, heart or kidney problems, or any serious medical condition, do not use essential oils without the advice of your health professional.

Be aware of these seven toxic oils.

  • Pennyroyal - an infusion of the leaves makes a safe digestive tea, but the essential oil can kill when taken internally.
  • Calamus - the European calamus contains a cancer causing terpene called thujone that is toxic to the nervous system. The American calamus is free of this chemical and is safe. The identity of the calamus oil is uncertain - so don't use it internally.
  • Wormwood - oil has an active ingredient called absinthe which is mind altering. It also contains thujone. Don't use the oil internally without the supervision of a herbalist.
  • Tansy - oil also contains thujone and is also very toxic.
  • Wormseed - was traditionally used to kill worms but the oil is highly toxic and has killed children who were given too much.
  • Wintergreen - the oil contains a toxic terpene called methyl salicylate which is in the same class as aspirin. People use it externally to relieve aches and pains of neuralgia and arthritis.
  • Camphor - The essential oil occurs in a semi-solid buttery state at room temperature (not as a liquid as 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. Camphor is commonly used externally in products to clear the nasal passages, open the chest, stimulate circulation and relieve pain.

It is best to avoid using an essential oil internally - but always seek the advice of a herbalist before use internally. In addition do not use the following essential oils if you have:

  • high blood pressure: hyssop, rosemary, sage or thyme.
  • epilepsy: sweet fennel, hyssop, sage, rosemary and wormwood
  • skin irritation: allspice, basil, bay, birch, bitter almond, black pepper, cassia, cinnamon leaf, cinnamon bark, citronella, clove bud, costus, cumin, fennel, fir needle, ginger, lemon, lemon grass, lemon verbena, melissa, myrrh, oak moss, orange peppermint, oregano, parsley seed, peppermint, pimento berry, pine, tagetes, tea tree, red and wile thyme and wintergreen.

The following essential oils will make your skin more sensitive to sunlight: all citrus oils, angelica, bergamot, lemon, mandarin, orange and lemon verbena.

If essential oils get into your eyes immediately flush with cold milk or vegetable oil to dilute. If stinging persists, seek medical attention. If undiluted essential oils get onto your hands use cream or vegetable oil to dilute and wash with soap and warm water. Repeat this process if necessary.

The following essential oils are safe to use on the skin during pregnancy:

  • chamomile
  • grapefruit
  • jasmine
  • lavender
  • neroli
  • rose
  • ylang-ylang

Do not be scared to use essential oils, just learn these simple precautions and follow them. Always be cautious.



Hobbs, C. 1998, Herbal Remedies for Dummies. IDG.

Hoffmann, D. 2000, The New Holistic Herbal. Element Pub.

Hoffmann, F. and Manning M. 2002, Herbal Medicine and Botanical Medical Fads. The Haworth Press.

McIntyre, A. 1995, The Complete Women's Herbal. Henry Holt Reference Books.

Woodward, P. 2003, Grow Your Own Herbal Remedies. Hyland House.

Marcin, M. M. 1990, Herbal Teas: Growing Harvesting and Brewing. Collins.

Shaw, N. 2002, Herbalism. Element.




The Health Gazette

Manage Your Newsletter Subscription

Personal details used only by us and not given to others for any reason.