Eucalyptus Oil: The Benefits & Uses Of This Distinct Scent

If you've ever taken a whiff of eucalyptus essential oil, you know the stuff is strong! As it turns out, that intense aroma signals some pretty potent antimicrobial and anti-inflammatory properties. Here's everything you need to know about this popular essential oil, its potential health benefits and side effects, and how to use it properly.

Eucalyptus oil is produced in the glands of many species of eucalyptus trees (there are more than 400 in total), which are native to Australia, Tasmania, and other nearby islands. Eucalyptus globulus, which is more commonly known as "Blue Gum," is the main source of eucalyptus oil used around the world today.

Eucalyptus oil's history of medicinal use dates back to the days of Indigenous Australians, who used both the leaves and the roots of the plant as medicines. When English colonists began to arrive in Australia in the late 1700s, they quickly adopted eucalyptus oil as a medicinal treatment themselves. In fact, when Surgeon-General John White arrived in 1788, he took an interest in eucalyptus almost immediately, according to entries in his diary. By 1790, he had distilled a quart of eucalyptus oil and sent it back to England for testing, where it eventually came to be used as a disinfectant to clean wounds and aid in healing after surgery.

The purported 1health benefits of eucalyptus oil are wide-ranging, but more high-quality research is needed before many of these anecdotal claims can be taken as official recommendations. Nevertheless, here are some of the most promising research-backed benefits of eucalyptus oil to date:

This powerful oil holds promise as a topical pain reliever2, particularly after workouts. Research has also found that patients with arthritis reported less pain and improved mood after topical application of lavender, marjoram, eucalyptus, rosemary, and peppermint essential oils3, which were diluted with a carrier oil.

The anti-inflammatory properties of eucalyptus oil4 may be to thank for these pain-relieving properties. (A 2010 study found that eucalyptus oil reduced the expression of the inflammatory COX-2 enzyme by at least 25%.)

In a 2016 study5, researchers found that eucalyptus oil possessed a "wide spectrum of biological activity" that included antimicrobial and fungicidal properties. In a separate study, eucalyptus oil was found to be effective in fighting against Trichosporon ovoides6, the fungus behind Piedra, a fungal infection occurring in the hair shafts on both head and body hair.

For those with infected toenails in particular, eucalyptus may "provide an acceptable and cheaper alternative to prescription topical antifungal agents," according to one study in the Journal of Foot and Ankle Research7.

Due to eucalyptus oil's antifungal properties, it can also be used as an air purifier. One 2017 study found that antifungal essential oils were able to help combat the fungus and mold present in indoor air, which can make their way into your home after building up in air vents. Using a eucalyptus oil in an diffuser may be particularly beneficial for this purpose.

There's evidence that eucalyptus promotes hair growth8, as well as treats dandruff. According to a 2012 report, eucalyptus oil's antifungal and antiseptic properties suggest that it would be a viable anti-dandruff treatment when incorporated into products like shampoos.

Eucalyptus oil may also be an effective natural treatment for head lice. One 2017 study9 from Australia, for example, found that using eucalyptus oil in a solution with lemon tea tree oil was twice as effective as the common chemical pesticide treatment piperonyl butoxide. Another previous study found that eucalyptus oil could actually protect human hair10 from the invasion of head lice for at least seven hours.

One study11 found that eucalyptus oil may have antibacterial effects on pathogenic bacteria in the upper respiratory tract. The oil has also been used as a natural way to relieve cold symptoms like coughing and sore throat. That's because eucalyptus oil's active compound 1,8-cineole can help clear mucus from airways and acts as a natural cough suppressant12, which is probably why eucalyptus oil is a key ingredient in popular products like Vicks VapoRub.

Another area with some research supporting eucalyptus oil's benefits is dentistry. Thanks to its antimicrobial properties, the oil seems to help fight off the bacteria 13responsible for tooth decay. One study published in the Journal of Periodontology even concluded that adding eucalyptus extract to gum14 could help promote good dental health and freshen breath.

In some traditional medicines, eucalyptus is used to treat diabetes15. While the scientific research on its blood sugar-balancing effect is slim, one study on diabetic rats16 found that eucalyptus oil did reduce their symptoms. Again, more research needs to be done before this becomes a legitimate Rx.

Eucalyptus oil can be inhaled or used topically to reap its varied benefits. Here are few suggestions and tips for each:

One of the most popular ways to use eucalyptus oil is via inhalation. You can inhale eucalyptus oil by taking a whiff directly from the bottle or by adding one to three drops to a cotton ball or towel and then breathing them in. Even easier, add a few drops to an essential oil diffuser to reap its aromatic benefits for a few hours.

You can also add eucalyptus essential oil to your bath for a steamy, sauna-like experience. Try this: Add about 1 to 2 cups of Epsom salts along with 1 tablespoon of a carrier oil (you can use coconut, jojoba, or sweet almond, among others) to a tub of warm water before adding no more than 3-6 drops of eucalyptus essential oil and swirling the bathwater before you jump in. 

If you're using the eucalyptus oil for pain relief of fungal infections of the skin, first blend it with a carrier oil, then massage it into the problem area. When you're first starting out, a good ratio of essential oil to carrier oil is about 2-3 drops essential oil to 1 teaspoon of carrier oil (for a 2% dilution).

If you want to treat dandruff, you can add a couple of drops of eucalyptus oil to your shampoo. Or, combine 2-3 drops of eucalyptus oil with a carrier oil and massage directly into your scalp. Allow to sit about 30 minutes before shampooing. Here's more information on how to use essential oils for lice.

As mentioned above, you can also add 1 drop of eucalyptus oil to your toothpaste before brushing to promote gum health, or create a mouth rinse by diluting 1 drop of eucalyptus oil with olive or coconut oil. However, you should never swallow eucalyptus oil.

If you plan to use eucalyptus oil to treat any particular condition, you should always consult your doctor first. There are some groups of people who should avoid eucalyptus oil altogether, including young children and pregnant women. The U.S. National Library of Medicine deems the oil likely unsafe for children, as it may impair or slow breathing. While the oil may be safe for pregnant women, it's still not recommended until more research looks into the potential side effects and impacts on the health of the fetus.

Most essential oils, including eucalyptus oil, are far too caustic to be applied directly to the skin without a carrier oil. If you do so, you will likely experience significant irritation.

Finally, there's always the potential for allergic reactions to eucalyptus oil17, especially with topical use. If you're allergic to tea tree oil, you will likely be allergic to eucalyptus oil, since they contain many of the same compounds18. 

Eucalyptus oil's antimicrobial compounds make it a promising pick for relief from joint and muscle pain, colds, gum disease, and more. As with all essential oils, you need to be careful not to swallow it or apply it directly to your skin. Remember, plant medicine is powerful stuff!