10 health benefits of eucalyptus leaves, backed by science

Claire Chamberlain
·8-min read
Photo credit: Yu Tsai for Harper's Bazaar
Photo credit: Yu Tsai for Harper's Bazaar

Eucalyptus can help with everything from easing colds and congestion, to boosting immunity, combatting skin problems and even dental hygiene.

What is eucalyptus?

Native to Australia although a few species can be found in warm regions the world over, the eucalyptus can vary in form from a small shrub to a towering evergreen tree, depending on the species. Its leaves can be small and round or long and flowing but are characterised by a blue-green hue, as well as a distinctive smell, which is often described as mint and pine, sometimes with a hint of citrus.

Eucalyptus health benefits

Aside from its distinctive fragrance, eucalyptus is believed to hold a number of important potential medicinal uses. Some eucalyptus uses might be familiar while others might be new to you:

1. Nasal congestion, colds and respiratory problems

If you’ve ever applied a vapour rub or taken a natural cold or cough remedy when you’ve been struck down by a head cold or respiratory infection, you’ll already be familiar with eucalyptus’s reputation as a decongestant. Indeed, eucalyptus is widely used as a key ingredient in these over-the-counter remedies, due to the presence of the compound cineole, found in eucalyptus leaves. Several research studies have proven the efficacy of cineole in the treatment of cold symptoms, including nasal congestion and coughing, with one study showing that the use of cineole for acute bronchitis helped relieve symptoms in four days. And in a 2012 study of children aged between two and 11 years, parents rated a vapour rub containing eucalyptus oil as being the most effective cough and cold treatment, compared with control groups.

But just what makes eucalyptus oil so effective? "Eucalyptus oil is an anti-inflammatory agent and works to ease congestion by shrinking swollen blood vessels in the nasal passage," explains Abbas Kanani, a pharmacist at Chemist Click. "This reduces the swelling and thickness of the lining of the nose, which causes congestion. As this eases, so does nasal congestion."

2. Pain relief

Eucalyptus oil may help to relieve pain. A 2013 study found that post-operative knee replacement patients found the inhalation of eucalyptus oil decreased pain (as well as blood pressure), while a South Korean study into the effects of aromatherapy on pain and depression (which included eucalyptus, among other oils), concluded that aromatherapy has major effects on decreasing pain and depression levels.

3. Immunity booster

People often try to strengthen their immune system by upping the vitamins and minerals in their diet. But what if essential oils played a part, too? A study published in BMC Immunology has shown eucalyptus oil to be highly promising in the immunity department, with researchers finding that it enhances the immune system’s phagocytic response to pathogens. In other words, it increases the body’s white blood cell count when germs are present.

4. High antioxidant levels

While it’s usually inhaled as a decongestant or applied topically, eucalyptus is packed with antioxidants (namely flavonoids) if you’d prefer to ingest it as a tea. Indeed, eucalyptus leaves are rich in catechins, luteolin and quercetin, to name just a few, and have been shown to have neuroprotective properties, helping to guard against oxidative stress. This can help to protect against everything from dementia to cancer, to heart failure.

5. Oral health improvement

Suffering from gingivitis, bad breath or dental plaque? Then you might want to add eucalyptus to your oral care routine. A study published in the Journal of Periodontology found that chewing eucalyptus extract gum for 12 weeks significantly reduced plaque accumulation, gingival index, bleeding on probing and periodontal probing depth in adults.

6. Stress reduction

Could stress management be as simple as inhaling the scent of eucalyptus on a regular basis? Apparently so. In a study published in the journal Evidence-based Complementary and Alternative Medicine, researchers found that preoperative anxiety was reduced in patients who inhaled eucalyptus oil. It’s all down to the cineole again, a major component of eucalyptus leaves.

7. Eases dry skin and scalp conditions

If you suffer with dry skin or a flaky, itchy scalp, look no further than this wonder leaf. A study has found that topical application of eucalyptus extract boosts ceramide levels in the skin (the fatty acid responsible for moisture retention), due to the compound Macrocarpal A, a major component of eucalyptus extract.

8. Antimicrobial properties

Long used as traditional medicine by aboriginals, studies have proven that eucalyptus does have the potential to fight infection with its antimicrobial properties. A 2012 study published in the Asian Pacific Journal of Tropical Biomedicine found that the essential oil extracted from eucalyptus leaves had antimicrobial activity against the bacteria E. coli and S. aureus. The study authors concluded that eucalyptus leaves could be exploited as a natural antibiotic for several infectious diseases caused by these germs.

9. Acts as an insect repellant

Eucalyptus has a heap of powerful benefits, meaning many of us love it. But you know who doesn’t like it? Insects. In fact, one 2011 study found eucalyptus oil offered 93.37 per cent protection against mosquito bites with a protection time of up to 240 minutes.

10. Kills head lice

Eucalyptus oil may be an alternative treatment for head lice. In fact, a study published in the Australasian Journal of Dermatology found that a head lice treatment containing eucalyptus essential oil was more than twice as effective at treating head lice infestation as traditional treatments, and in vitro exposure of eggs and lice to the eucalyptus solution resulted in 100 per cent mortality.

Photo credit: Oleksandr Pupko - Getty Images
Photo credit: Oleksandr Pupko - Getty Images

How to use eucalyptus

A word of warning: you can’t eat eucalyptus leaves fresh, due to toxicity. So what are the best (and safest) ways to reap the benefits of eucalyptus?

Eucalyptus essential oil

Eucalyptus oil is made from the essential oils extracted from the leaves of certain species of the plant. Use by adding a few drops to a diffuser steamer or bath, for an at-home aromatherapy session. You can also apply eucalyptus oil topically by adding to a carrier oil (such as coconut, sunflower or argan) and massaging on to your skin.

Eucalyptus tea

To reap the antioxidant benefits of eucalyptus, make eucalyptus tea by infusing half a teaspoon of dried, ground eucalyptus leaves in boiling water for five minutes. Sweeten with honey if desired.

Dried eucalyptus leaves

Hanging dried eucalyptus leaves in your bathroom will infuse the steam from your bath or shower with the invigorating scent.

Over-the-counter eucalyptus products

Many over-the-counter pharmaceutical products, from vapour rubs to mouthwashes, already harness the power of eucalyptus.

"Eucalyptus is commonly found in pastilles, as it can help to relieve nasal congestion and can soothe irritation in the throat," says Kanani. "You can also purchase eucalyptus crystals, which can be sprinkled onto hot water to make steam. Eucalyptus can also be found in certain creams and rubs that can be applied to the body to provide a soothing effect."

Is eucalyptus oil safe to use?

While eucalyptus oil offers some great health benefits and is generally considered safe if used properly, there are some important factors to take into consideration:

• Eucalyptus oil toxicity

As we’ve said, fresh eucalyptus leaves are toxic if consumed, so never ingest them. It’s also important that you never add eucalyptus oil to food or drinks, for example, to make tea. The oil is also toxic when ingested. Instead, buy eucalyptus tea bags or use dried leaves when preparing tea.

• Eucalyptus and children

While it’s an ingredient in the vapour rubs commonly used to ease congestion in children, it’s important to note that, due to its rapid absorption, eucalyptus oil can be highly toxic to children. Because of this, it’s vital to keep eucalyptus oil out of reach of children (in an Australian telephone survey, 74 per cent of preschoolers had gained access to eucalyptus oil via a home vapourising unit placed on the floor). And while 82 per cent of children with eucalyptus oil poisoning remained asymptomatic, there have been far more serious cases: toxicity in children can lead to vomiting, drowsiness, headaches, seizures, coma and even death.

And it’s not just ingestion: children have become ill from topical application, too, if too high a concentration of eucalyptus oil is used, so always consult a pharmacist or doctor before use.

• Eucalyptus skin irritation

Topical application may cause skin irritation, so be mindful when applying.

"If you are using eucalyptus oil on your pillow, clothes, or even directly onto your skin, you should take care if you have skin conditions such as eczema or psoriasis, as eucalyptus can irritate sensitive skin," says Kanani.

• Eucalyptus contraindications

As with any essential oil or alternative therapy, it’s important to consult a medical professional before commencing use, especially if you are taking other medication. Eucalyptus oil may interact with other medicines, including those used to treat high cholesterol and mental illnesses. And it can also interfere with existing health conditions.

"If you are inhaling eucalyptus oil, you should take care if you have a condition that affects your breathing, such as asthma or COPD, as eucalyptus oil may exacerbate these conditions," warns Kanani.

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