Essential Oils : A Guide to Eucalyptus

The medicinal properties of eucalyptus have long been treasured, and its essential oil has become so popular that Australia, the original source of the plant, is no longer the primary source. Asia, Africa and even South America are all cultivating this wondrous plant as more and more people begin to enjoy the health benefits that it offers.

The History of Eucalyptus

The indigenous peoples of Australia have used eucalyptus oil as a treatment for congestion, fever, aches and pains, and symptoms of cold and flu. This traditional medicine began its spread to the rest of the world when British settlers set out for the continent and began distilling oil from the plant to treat the early colonists.

Dennis Considen and John White, who were physicians for some of the first colonists, began distilling oil from some eucalyptus species in 1788. Even so, it took a long time for eucalyptus oil to become popular in the rest of the world.

A Melbourne pharmacist, Joseph Bosisto, began exploring the commercial potential for the oil and set up the first commercial distillery in 1852 near Dandenong, Victoria to start extracting essential oils from the plant. He started with the species Eucalyptus radiata, which is still one of the most widely used species today.

The active ingredient in eucalyptus oil, Eucalyptol, was identified by F.S. Cloez in 1870. By the 1880s, eucalyptus oil was a common antiseptic used during surgery.

Production of the oil was further spurred on as it was a byproduct of exploitation of eucalyptus timber. Today, this oil sees varying uses, ranging from medicinal and aroma-therapy applications to food-flavoring and industrial uses. By far, though, the primary use for the oil is in pharmaceutical preparations, including ointments, cough drops and decongestants.

Where is Eucalyptus Grown?

While its homeland is Australia, eucalyptus as a crop has spread worldwide, and that country’s share of the world’s production peaked in the 1940s. China currently produces about 70 percent of the world’s eucalyptus oil. Portugal, Spain and Australia produce and process their own eucalyptus in significant amounts as well.

Despite its medicinal properties, the plant is used in most of the world as mere decoration, not for essential oil production. Most of the commercially cultivated oils are imported by Europe, which is the largest consumer of the medicinal products created from eucalyptus. Brazil and India also produce various species, and Brazil is the only supplier of staigeriana oil. France, Germany and the UK import a lot, but the US is still the largest single market for eucalyptus essential oil.

Species Used for Essential Oils

There are actually hundreds of plant species within the genus Eucalyptus, all of which are trees and shrubs that dominate the indigenous Australian landscape. Only 15 species occur outside of that continent, but they are cultivated all over the world. The species used in essential oils are typically those with the best fragrance or a high level of Cineol and Eucalyptol.

Eucalyptus Globulus: One of the most widely used species for essential oils, globulus has a very herbaceous scent with soft woody undertones.
Eucalyptus Blue Mallee: Has the highest Cineol content and Eucalyptol, an antiseptic, which makes it the strongest antiseptics among the Eucalyptus.
Eucalyptus Lemon: This oil has a slightly camphoraceous odor with a sweet, citronella scent.
Eucalyptus Radiata: This type of eucalyptus has a crisp, clean aroma and includes some subtle back notes of citrus and floral.

Often, it can be confusing for regular consumers to determine which type of eucalyptus they’re actually getting because so many manufacturers simply label them with the genus, Eucalyptus, not the individual species name. We’ll go over the medicinal properties shortly, but these species are typically what you’ll encounter as the primary sources of essential oil as they’ve been used for thousands of years.

Other Uses for Eucalyptus Oil

Aside from its medicinal uses, eucalyptus makes it into a number of other products and processes. You’ll often find it as an ingredient in candy, toothpaste and air fresheners. It also works well as an insect-repellant, so you’ll often find it as an ingredient in mosquito repellant and insect repellant candles.

A few species of eucalyptus, primarily mallees, can produce oil that has a useful mixture of volatile organic compounds that can be used as an industrial solvent and as an environmentally friendly pest-control and weed-control product. It has even been used as an additive in ethanol-fuel blends and has a large potential as a component in fossil-fuel replacements.

How Eucalyptus Oil is Made

Like many essential oils, eucalyptus is distilled from its plant of origin. The leaves of the plant are crushed and then steamed at high temperature to release the oil. The resulting oil-water mixture is then distilled, removing any impurities (such as the tannins and leaf material).

After distillation, the cooled water and oil are easily separated so that only premium-grade eucalyptus oil remains. The final product is a pale, fragrant, yellow liquid that makes its way into soaps, aromatics, analgesics and other hygiene products.

Purity and Quality of the Oil

The medicinal value of this natural remedy lies primarily in its cineol (or eucalyptol) content. Most essential oils from eucalyptus are sold with at least 70% eucalyptol content, although you can find oils marked with even higher concentrations to upwards of 90%. This concentration isn’t critical, though, since most preparations require that you dilute the oil properly before using it; otherwise, ingesting or applying it can be toxic.

The concentrations present in essential oils depend on which species of eucalyptus they came from, as well as the distillation process and other blending that producers may do before they bring the oil to market. Eucalyptus oil from China is frequently traded with more than 80% eucalyptol content.

Aromatic qualities are also important if you wish to use this oil as an inhalant. The chemical compound that gives it such a fragrant aroma is called citronella. The international standards that exist for the purity of eucalyptus specify that the aldehyde content in the oil be at least 70% in order to reach pharmacopeia grade.

Medicinal Properties of Eucalyptus Oil

Because if its properties as a decongestant and its desirable aroma, eucalyptus is employed in a vast range of products, from pure oils meant for dilution and medicinal applications to simple soaps and moisturizers.

Scientific studies on eucalyptol (cineole) have been done attempting to uncover its various effects, which include helping to control mucus in airways and relieving asthma. The active ingredient in eucalyptus oil has also been found to be an effective treatment for sinusitis, nasal congestion, headache and skin inflammation.

Antiseptic Treatments

The antimicrobial, antifungal and antibacterial nature of eucalyptus species (particularly blue mallee) has caused people to include it in many medicinal preparations, and you’ll often find it combined with other essential oils and medicines. These antiseptic properties make it a common ingredient in applications applied to small wounds, scratches, insect bites, burns and other sores. Its analgesic properties also help it to relieve irritation.

To use this essential oil, you can add it to topical treatments for cuts and scrapes, rub the diluted oil into sore muscles, massage the dilution into your temples and forehead or add it to hand cream, soap and shampoo to aid with skin care.

Used as an Inhalant

Anti-inflammatory effects make eucalyptus oil helpful in relieving congestion, which is often an effect of inflamed sinus passages. When diluted properly, the essential oil can be taken by mouth to help relieve inflamed mucous membranes in the nose and mouth to help treat sinus pain, bronchial swelling, asthma and a whole host of respiratory issues. It’s also used to help loosen coughs and relieve cold or flu symptoms, often deployed along with vaporizer fluids and humidifiers.

Aroma therapists often employ eucalyptus to help their clients relax, taking advantage of the more aromatic species like globulus, lemon and radiata to provide a soothing effect that reduces stress and promotes relaxation.

To use eucalyptus as an inhalant, you can add it to a warm bath, release it in a steam room or sauna and even combine it in a nebulizer or humidifier with warm water to vaporize it.

Applied to Control Blood Sugar

Eucalyptus is one of the plants traditionally used to treat high blood-sugar in diabetics. Studies on the effects of the active elements within the essential oil are still being conducted to confirm and quantify just how blood-sugar levels are affected.

Blending with Other Essential Oils

Eucalyptus is frequently blended with a variety of other oils, but essential oils of helichrysum, lavender, tea tree, cedarwood, ginger, thyme and lemon grass are very beneficial and soothing combinations.

Use with Caution

There’s still a lot of scientific study to be done on the benefits and health effects of eucalyptus, so you should be very deliberate about how you use this essential oil and always seek advice from your health professional to make sure it’s safe for you to use.

Undiluted eucalyptus oil can be harmful when taken by mouth or applied directly to skin, and taking too much can actually be fatal. Eucalyptol, a chemical that is removed from eucalyptus oil and used as medicine, appears to be safe when taken by mouth for up to 12 weeks. If you notice stomach pain and burning, dizziness, nausea, vomiting, weakness, trouble breathing or contracted pupils, you should contact your doctor immediately.

Eucalyptus is not recommended for women who are pregnant or breastfeeding. They should avoid applying eucalyptus oil as an inhalant or topical treatment, although it appears to be safe when ingested in small amounts in food.

The National Health Institute has advised against using eucalyptus for children. Children should not take it by mouth, ingest large amounts through food nor apply it to their skin.

Even though research is revealing interesting things about how eucalyptus may affect blood sugar levels, the NIH has issued advice that patients should stop using it 2 weeks before and after a scheduled surgery as it might make blood sugar difficult to control. It may also interfere with diabetic medications and cause unhealthy drops in blood sugar. Check with your doctor before you add this essential oil to your existing treatment.

You should also be careful about possible interactions between eucalyptus and other herbal supplements, as some interactions can cause liver damage. Check with your doctor to ask about medications you are currently taking.

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