The 5+ Benefits of Eucalyptus
Eucalyptus (Eucalyptus globulus) is an evergreen tree native to Australia but cultivated worldwide. It was first used by the Aborigines in the dry outback—they chewed the roots, which hold a high concentration of water. They also drank eucalyptus tea as a remedy for fever. As this use spread, eucalyptus became known as Australian fever tea.
The highly concentrated oil that's steam-distilled from the leaves of the tree has been used medicinally since at least 1788, when doctors reportedly noted the presence of the oil and began using it to treat chest problems and colic. In the late 1800s, its ability to promote sweating and clear mucus led to eucalyptus oil being prescribed for respiratory conditions including bronchitis, flu, asthma, and coughs. As word about eucalyptus oil spread, it began to be used in other ways, including as a liniment for tired, sore muscles, and to ease the pain of arthritis. Though the essential oil is still recommended today for a host of medicinal applications, its primary use remains the treatment of cough, cold, bronchitis, and symptomatic relief of colds and congestion of the upper respiratory tract.
Like most essential oils, eucalyptus oil contains many natural components. But the key one is 1,8-cineole (aka cineole and eucalyptol), the compound that's responsible for its clean, sharp, slightly medicinal smell as well as its medicinal value. According to a 2010 review, eucalyptol has been shown to have strong antibacterial, antiviral, and anti-fungal action, which may explain its traditional use as a treatment for respiratory ailments. That said, in a more recent study from 2018 that investigated the antibiotic activity of five essential oils, eucalyptus oil only showed weak activity against respiratory pathogens. Eucalyptus oil was found to be a potent antioxidant in a 2010 phytochemical screening.
Few of the proposed benefits for eucalyptus oil have strong science behind them, according to the Natural Medicines Comprehensive Database (NMCD), which rates effectiveness based on scientific evidence. Though promising, most evidence is considered preliminary. Here's a rundown on what's known so far about how eucalyptus oil can benefit health.
Cold and Respiratory Relief
You may know eucalyptus oil best from products like Vicks VapoRub, where it acts to clear your airways. At least one study published in 2012 found some benefit for a vapour rub (VR) containing camphor, menthol, and eucalyptus oil compared to a petroleum placebo when used on children at nighttime. Between treatment groups, researchers detected significant differences in improvement in cough, congestion, and sleep difficulty, with the VR group consistently scoring the best over placebo for cough severity, child and parent sleep difficulty, and combined symptom score. There was no effect on runny nose, and VR-treated children experienced some skin redness and burning.
Eucalyptus oil is often used in the form of steam inhalation to help ease cold symptoms, though studies are needed to confirm the value of this use. When inhaled into the respiratory system, it's believed to reduce the muscle spasms that can narrow your airway and make it difficult to breathe. It's also said to be a gentle expectorant and to promote drainage from congested sinuses.
In traditional herbal medicine, eucalyptus tea or oil is often used internally as well as externally over the chest. Both uses are approved by the German Commission E, the expert panel that evaluates herbal medicine, to treat bronchitis. This condition is a common inflammation of the lining of the tubes that carry air to and from your lungs that often develops from a cold. A double-blind, placebo-controlled study published in the journal Cough in 2013 confirmed that people with bronchitis may benefit from treatment with oral cineole. Over a period of 10 days, 242 patients received either 200 milligrams of cineole three times a day or a placebo. After four days of treatment, it was notable that the group treated with cineole showed significantly more improvement in symptoms of acute bronchitis, especially the frequency of coughing fits.
Cineole may help speed the healing of acute sinusitis, which often starts as a cold and then turns into a bacterial infection. In a 2004 double-blind study of 150 people with acute sinusitis that did not require treatment with antibiotics, those given 200 milligrams of cineole orally three times a day recovered significantly faster than those given a placebo.
Early research shows that eucalyptol might be able to break up mucus in people with asthma. While some people with severe asthma have been able to lower their dosage of steroid medications by taking eucalyptol, you shouldn't try this without your healthcare provider's advice and monitoring.
Topical ointments containing the oil have been used in traditional Aboriginal medicine to support wound healing, a use that modern science has investigated. A study from 2012 looked at the antimicrobial activity of eucalyptus oil against two pathogens, S. aureus, which is mainly responsible for post-operative wound infection, toxic shock syndrome, and food poisoning, and E. coli, which is responsible for urinary tract infections. Researchers found that the oil had activity against both bacteria. This type of antibacterial action may make eucalyptus oil an effective treatment for minor cuts and wounds, says herbal expert Michael Castleman, the author of "The New Healing Herbs." He suggests applying a drop or two of eucalyptus oil to a clean wound.
Like many essential oils, eucalyptus oil is being investigated for its use as a pain reliever. In a 2013 study, inhalation of eucalyptus oil for 30 minutes on three consecutive days following knee replacement surgery was effective in decreasing patients' pain and blood pressure.
A eucalyptus-based ointment was found to increase circulation when applied to the forearms of participants in a small double-blind study published in 1991, which suggests that eucalyptus may temporarily ease minor muscle soreness when applied topically. Like menthol and wintergreen, eucalyptus is considered a counterirritant. It works by irritating the skin where it's applied, causing the skin to feel hot or cold.
Early research published in the Journal of Periodontology shows that chewing gum containing 0.3 percent to 0.6 percent eucalyptus extract can reduce dental plaque and gingivitis, and improve bad breath in some people. Some dentists recommend diluting one drop of eucalyptus oil with olive or coconut oil and swishing in your mouth or applying one drop to your toothpaste before brushing.