Eucalyptus… you likely know that it is the main food of Australia’s cute koalas, and that it can be found in many cold and flu remedies, but what else do you know about it? Read on to discover some of the remarkable healing qualities of eucalyptus essential oil, together with the latest research on it’s health-boosting and protective properties.
Belonging to the myrtle plant family Myrtaceae, the word “eucalyptus” comes from the Greek word “eukalyptos” meaning “covered” or “wrapped.” This refers to the woody seed pod of the eucalyptus tree which dangles down from the branches and almost completely covers the eucalyptus blossoms. There are well over 900 different species of eucalyptus, both trees and shrubs.
Most eucalyptus species grow in Australia. In fact 75% of trees in Australia are some variety of eucalyptus. They are also found in Indonesia, New Guinea, South Africa, California, and are being cultivated in many other tropical and subtropical regions as well.
One of the best times to be in a forest of eucalyptus breathing in its heady aroma is during the summer when the sun’s heat releases the oil from the leaves. In fact, if you stand on a hill overlooking a eucalyptus forest, you will notice a sort of blue haze hanging over it. That blue haze is the oil being emitted from the trees (which by the way are among the tallest on earth)!
How Eucalyptus Essential Oil is Made
Eucalyptus essential oil is steam distilled from the leaves of the trees. It takes about 50 pounds (22.6 kilograms) of eucalyptus leaves to yield one pound (453 grams) of essential oil.
The most commonly used eucalyptus varieties for aromatherapy purposes have traditionally been Eucalyptus globulus and Eucalyptus radiata. But science is discovering that dozens of other varieties of eucalyptus have excellent healing qualities as well.
Ancient Aboriginal Uses of Eucalyptus
Australian aboriginal people have a history dating back tens of thousands of years and they used eucalyptus extensively for healing. They bound the leaves around serious wounds to prevent infection and promote healing. They knew the fresh, lung-opening aroma to be excellent for clearing respiratory congestion, and that it helped to suppress coughing.
They used eucalyptus to repel the ever-present outback flies and insects, and employed eucalyptus as a rub for sore muscles, joint pain, and headaches. Sometimes they would burn the leaves and inhale the smoke to relieve a fever. Even the resin of the eucalyptus tree was collected, boiled, and used as a disinfectant for treating cuts, sores, and other painful conditions.
Other cultures use eucalyptus as well. For instance, traditional Chinese and Indian medicine employed the use of eucalyptus for a wide range of medical conditions.
How Eucalyptus Essential Oil Was Brought to the West
In 1848, Joseph Bosisto, a young pharmacist from Yorkshire, England, arrived in Australia thinking he was going to take part in the Victorian gold rush. Instead, he began to investigate the healing properties of Australian plants − specifically eucalyptus. In 1852 he began distilling eucalyptus oil, making it one of the oldest commercially available oils. Eucalyptus oil became a highly sought-after medicinal oil; it even won prizes in 17 international exhibitions in 1891!
Eucalyptus was used extensively during both World Wars. It was used to control meningitis and influenza outbreaks, and to cleanse wounds when other anti-bacterial supplies ran out. In the 1940s and 50s many cold and cough medicines contained eucalyptus oil for it was widely known then for its ability to ease those conditions.
Potent Phytochemicals Found in Eucalyptus
There are over one hundred potent phytochemicals (natural plant-based chemical compounds) in eucalyptus oil. The phytochemical content varies between eucalyptus varieties and chemotypes. Some plants generate different chemical constituents within a genus and the chemotype denotes this difference.
Sometimes the distilling process employed creates different phytochemicals. Some of the main compounds in eucalyptus essential oil include citronellal, aromadendrene, alpha-phellandrene, beta-phellandrene, alpha-pinene, beta-pinene, piperitone, (E)-methyl-cinnamate, para-cymene, gamma-terpinene, 1,8-cyneol (eucalyptol), geraniol, geranial, and many more.
Extensive Research into the Many Health Benefits of Eucalyptus
A Safe Alternative to Insect Repellent
In 2012, Argentinian researchers investigated 15 different species of eucalyptus and found that they all had the ability to kill the larvae of the mosquito that causes Yellow Fever, Aedes aegypti. In 2011, some of those same researchers reported in the Journal of Economic Entomology that several varieties of eucalyptus oil were toxic to Haematobia irritans, better known as the blood-sucking horn fly.
In 2009, UK researchers published a study in Experimental & Applied Acarology investigating four eucalyptus species. They found that they were toxic to the parasitic red chicken mite, Dermanyssus gallinae. Researchers made an interesting note, stating “There appeared to be a trend whereby the essential oils that were composed of the fewer chemical components were the least lethal to D. gallinae. It may therefore be the case that the complexity of an essential oil’s chemical makeup plays an important role in dictating the toxicity of that oil to pests.”
A 2009 article appearing in Science for Environment Policy discussed the interesting possibility that eucalyptus oil might prove to be a great alternative to chemical pesticides due to its natural ability to repel insects, microbes, and fungi. Also, essential oils do not persist for long in the environment as do chemical pesticides.
Eucalyptus Displays Strong Anti-bacterial Effects Against Staph & MRSA
Dozens of studies exist which attest to the ability of eucalyptus to kill many different strains of bacteria. Here are some of the most interesting studies:
2014 Indian research reported in Ultrasonics Sonochemistry found that a specially prepared nanoemulsion containing (in part) eucalyptus oil not only effectively killed Staphylococcus aureus (better known as golden staph) in an animal study, it also improved wound healing time.
A German study reported in 2011 in the journal Pharmaceutical Biology found that among the eucalyptus varieties studied, Eucalyptus globulus had the strongest activity against methicillin-resistant Staphylococcus aureus (better known as MRSA, currently rife in hospital settings).
In 2008, Italian researchers investigated Eucalyptus globulus essential oil and found it to be active against Haemophilus influenzae. This is a type of bacteria that mainly causes illness in babies and young children, more commonly known as H. influenzae type b, or Hib. This oil was also potent against H. parainfluenzae (involved in COPD), and against Stenotrophomonas maltophilia, a multi-drug resistant bug causing rampant and difficult to treat infections. In addition, it was potent against Streptococcus pneumoniae, involved in many illnesses including pneumonia.
Antiviral Activity Against E. Coli, Staph, Candida, and Herpes
Researchers in Tunisia released a 2012 study in BMC Complementary and Alternative Medicine which found that several varieties of eucalyptus oil had strong antibacterial, antifungal, and antiviral effects against common pathogens. Included amongst these are: E. coli, Streptococcus pneumoniae, Staphylococcus aureus, Candida albicans, and several others.
German researchers in 2001 investigating the antiviral activity of tea tree oil and eucalyptus oil found that both exhibited significant inhibition of both herpes simplex virus-1 and -2.
Anti-Inflammatory and Beneficial for Respiratory Disease
Science is discovering what ancient people have long known − that eucalyptus has the ability to aid respiratory diseases such as chronic obstructive pulmonary disease (COPD), asthma, bronchitis, the common cold, croup, influenza, and pneumonia. It appears to do this with the help of four potent phytochemicals (and there well may be more):
- Eucalyptol (aka 1,8-cineole). It helps to ease the inflammatory process, according to German research investigating its properties in inflammatory airway diseases. 2016 research released by Chinese scientists, reported in the journal Inflammation, also found that 1,8-cineol effectively stopped pulmonary inflammatory processes and protected against influenza viral infections in an animal study.
- Pinocembrin. Joint Australian and American research published in 2016 in the journal PLoS One has hit upon another fascinating phytochemical from certain varieties of eucalyptus: a flavonoid known as pinocembrin. It also has potent anti-inflammatory properties. Indeed, 2015 Chinese research also found that pinocembrin played a central role in inhibiting the inflammatory process.
- Gamma-terpinene. 2015 Brazilian research published in Planta Medica found that gamma-terpinene derived from eucalyptus alleviated acute inflammatory responses in animals.
- Ellagitannin. Egyptian research reported in 2015 in Phytomedicine indicates that a polyphenol known as ellagitannin from Eucalyptus citriodora had gastro-protective effects on rats with stomach ulcers due to its antioxidant and anti-inflammatory benefits.
Eucalyptus Essential Oil Helps to Regulate Blood Sugar
Many different cultures have used eucalyptus to help regulate blood sugar levels. Modern research is finally confirming that benefit.
Colombian researchers reported in 2015 that Eucalyptus tereticornis extracts increased glucose uptake in vitro (test tube study). Further, in diabetic mice this variety of eucalyptus reduced fasting glycemia, improved glucose tolerance, and reduced insulin resistance.
A 2014 joint research project published in World Journal of Diabetes found that the polyphenols and flavonoids in three eucalyptus species inhibited enzymes that played a role in type 2 diabetes. Eucalyptus globulus was the clear winner in this in vitro research study.
An Iranian research study published in 2009 in the Indian Journal of Clinical Biochemistry on diabetic rats found that the antioxidants in Eucalyptus globulus, after four weeks of administration, caused a significant decrease in plasma glucose levels.
Pain Relief and Reduced Blood Pressure
A 2013 Korean study reported in Evidence-Based Complementary and Alternative Medicine tested the effect of eucalyptus oil on pain relief with 52 patients who underwent total knee replacement surgery. The patients were divided into two groups. One group inhaled eucalyptus oil, while the control group inhaled almond oil. The eucalyptus oil group reported much lower levels of pain than those inhaling the almond oil. Also, the eucalyptus oil group enjoyed significant reductions in blood pressure.
Novel Japanese research reported in 2012 in the journal Molecular Pain found that 1,8-cineole from eucalyptus had analgesic and anti-inflammatory effects. This was due to its inhibition of something known as TRPA1, which is a thermosensitive receptor in humans.
Does Eucalyptus Essential Oil Have Anti-Cancer Benefits?
The phytochemicals alpha-pinene and beta-pinene (found in some varieties of eucalyptus) have been discussed at length for their anti-cancer properties, but many other anti-cancer compounds derived from eucalyptus are currently being researched.
2014 research from Jordan investigated six species of eucalyptus and found weak to moderate activity against non-lymphoma tumor cell lines. They also found potent cytotoxicity (meaning toxic to cancer cells) against lymphoma tumor cell lines.
Joint Saudi and Egyptian research reported in 2014 in Scientific Reports on extracts from Eucalyptus cinerea demonstrated they had moderate to potent cytotoxic activity against three human cancer cell lines. These include MCF7 breast cancer cells (hormone receptor positive cells), laryngeal carcinoma, and colon cancer cells.
2012 research out of the University of Rajshahi, Bangladesh, found that several varieties of eucalyptus reduced tumor growth rate and enhanced the lifespan of the mice in the study.
Eucalyptus may have a role to play in cancer, but more human studies need to be done.
Eucalyptus May Stimulate Immune Response
According to a study published by Italian researchers in 2008 in BMC Immunology, Eucalyptus globulus activated human monocyte derived macrophages, a part of cell-mediated immune response. The researchers also found that the immune systems of rats given a combination of eucalyptus oil and 5-fluorouracil (5-FU), a popular chemotherapy drug used in the treatment of different types of cancer, fared much better, nearly as well as untreated rats.
The researchers went on to state, “Thus, the present study stimulates further investigations also using single components of essential oil extracts from various species of Eucalyptus for development of a possible new class of immuno-regulatory agents useful as adjuvant in immuno-suppressive pathologies, in infectious disease as well as in tumour chemotherapy.”
Even More Health-Promoting Uses for Eucalyptus
Fighting Fever – Eucalyptus has long been known by native Australians as the “fever tree” because of its ability to help reduce a fever. Studies dating back to 1891 in The Lancet indicate eucalyptus oil was being used for scarlet fever.
Improved Brain Function – While there does not appear to be much formal research on the subject, eucalyptus essential oil has a long tradition of being used to stimulate mental activity. 2005 research out of Brazil, published in the Brazilian Journal of Medical and Biological Research, discusses the fact that eucalyptus is a vasodilator. This means it increases blood flow by relaxing blood vessels. That allows increased blood flow to various parts of the body, including the brain. More blood to the brain means better, clearer thinking. Eucalyptus has often been used in classrooms to increase student thinking and performance.
3 Ways to Use Eucalyptus Essential Oil
It’s best to purchase your eucalyptus essential oil from reputable companies that use proper distillation procedures and ensure a quality product. They should also indicate the genus species on the label (for instance Eucalyptus radiata or Eucalyptus bicostata or Eucalyptus globulus) so that you know exactly what you’re buying.
1. Inhalation. Eucalyptus provides instant relief for upper respiratory infections. Place a few drops of oil into your palms, rub them together, and place them over your nose and mouth (being careful to avoid the eyes). Breathe in deeply for a few minutes. This is the best method for getting the essential oil into your bloodstream so it can do its job. You can also diffuse eucalyptus in the room where you are working or sitting. Use a cool mist ultrasonic diffuser for best results. Do not heat essential oils as this can diminish their therapeutic benefits.
2. External Application. Using an organic carrier oil such as almond, jojoba, hemp, coconut, olive oil, etc, dilute and massage eucalyptus oil into the skin. You can also place a few drops of eucalyptus into one cup of epsom salts. Dissolve this mixture into a hot bath and soak. It’s great for sore muscles and also soothing for urinary tract infections.
3. Internal Application. Eucalyptus essential oil has been approved for human consumption by the United States Food & Drug Administration (USFDA). Eucalyptus globulus is the best one to take internally. Put a drop or two of Eucalyptus globulus in three to four ounces (about 100 ml) of liquid such as almond or rice, or soy milk. A few drops can also be added to one teaspoon of raw honey. Be sure to read “Precautions for Using Eucalyptus Oil” below before using internally.
Precautions for Using Eucalyptus Oil
Be sure to use a high quality, medicinal grade essential oil. Use of eucalyptus essential oil is not recommended for:
- Pregnant or nursing women
- Children under age six. In older children, be sure to dilute heavily.
- It can be dangerous to take high doses of eucalyptus oil. Always work with a qualified aromatherapist or health care practitioner.
- Eucalyptus can irritate those with sensitive skin. Be sure to dilute prior to using on sensitive areas such as face, neck, etc and always do a patch test first with a carrier oil before applying liberally.
It is not advisable to use any essential oil as a stand-alone therapy for cancer, or for any of the other health issues mentioned in this article. When used in combination with other conventional and complementary medical treatments, however, essential oils can be effective in helping the body heal… as well as protect against a number of health-harming pathogens.