Oil from the eucalyptus tree (Eucalyptus globulus) is used today in many over-the-counter cough and cold products, to relieve congestion. Eucalyptus oil is also used in creams and ointments to relieve muscle and joint pain, and in some mouthwashes.

In its native Australia, the eucalyptus tree is the main food for koalas. It's been used in the past as an antiseptic to kill germs and the oil was used in traditional Aboriginal medicines to heal wounds and fungal infections. Teas made of eucalyptus leaves were also used to reduce fevers. Eucalyptus was soon used in other traditional medicine systems, including Chinese, Indian (Ayurvedic), and Greek and European.

In 19th-century England, eucalyptus oil was used in hospitals to clean urinary catheters. Laboratory studies later showed that eucalyptus oil contains substances that kill bacteria. It also may kill some viruses and fungi. Studies in animals and test tubes also found that eucalyptus oil acts as an expectorant, meaning it helps coughs by loosening phlegm.

Plant Description

There are many species of eucalyptus. Some are the size of an ornamental shrub, and some grow to be giant trees. The kind most often used as medicine is called blue gum or Australian fever tree. It can grow as high as 230 feet. Its 4 - 12 inch leaves are dark green and shiny. Its blue-gray bark peels to reveal a cream-colored inner bark.

Medicinal Uses and Indications

It can be dangerous to take eucalyptus oil by mouth. Don't do it unless your doctor tells you to.

Cough and cold

Many medicines to treat coughs and the common cold contain eucalyptus. It's found in many lozenges, cough syrups, rubs, and vapor baths throughout the United States and Europe. Herbalists often recommend using fresh leaves in teas and gargles to soothe sore throats and treat bronchitis and sinusitis.

Eucalyptus ointments are also used on the nose and chest to relieve congestion. Eucalyptus oil helps loosen phlegm, so many people breathe in eucalyptus steam to help treat bronchitis, coughs, and the flu.

Plaque and gum disease

Eucalyptus oil is rich in cineole, an antiseptic that kills bacteria that can cause bad breath. Some antiseptic mouthwashes use eucalyptus, along with other oils, and have been shown to help prevent plaque and gingivitis.

Other uses

On the skin, eucalyptus oil has been used to treat arthritis, boils, sores and wounds. The oil is also used in some insect repellents, and one study found that an oil of lemon eucalyptus product may also keep ticks away.

What's It Made Of?

The leaves and oil of the eucalyptus plant are used as medicine. Eucalyptus oil is made from the fresh leaves and branch tops of the eucalyptus plant. Eucalyptus leaves contain tannins, which researchers think may help reduce inflammation, along with flavonoids or plant-based antioxidants, and volatile oils.

Available Forms

Eucalyptus oil is available in many products, including liquids and ointments. The leaves are available fresh, dried (to be used in teas), and in liquid extracts. Cough drops, syrups, vaporizer fluids, liniments, toothpastes, and mouthwashes may have eucalyptus oil or its active ingredient, cineole. Some of the familiar over-the-counter remedies that have eucalyptus oil include Listerine, Mentholatum Cherry Chest Rub, and Vicks VapoRub.

How to Take It


Do not give a child eucalyptus orally (by mouth), because it is toxic. Do not give cough drops with eucalyptus to children under 6.

For a cold, don’t put eucalyptus oil, salve or chest rub on the face or nose of a child under 2. Ask your doctor before using eucalyptus oil as a chest rub for your child or to inhale steam for congestion.


Do not take eucalyptus oil orally (by mouth) except under your doctor’s supervision.

Eucalyptus oil (to apply to the skin): add ½ - 1 mL (15 - 30 drops) of oil to 1/2 cup of carrier oil (sesame, almond, olive, etc.). To breathe in steam, add 5 - 10 drops of oil to 2 cups boiling water. Place towel over head and inhale steam


The use of herbs is a time-honored approach to strengthening the body and treating disease. Herbs, however, can trigger side effects and can interact with other herbs, supplements, or medications. For these reasons, herbs should be taken with care, under the supervision of a health care provider qualified in the field of botanical medicine.

For adults, eucalyptus oil is generally safe when applied to the skin. Don’t put eucalyptus oil, salve or chest rub on the face or nose of a child under 2.

People with asthma, seizures, liver or kidney disease, or low blood pressure should not use eucalyptus without first talking to their doctors.

Pregnant and breastfeeding women should not use eucalyptus.

Eucalyptus oil is toxic when taken by mouth. Do not take it except under your doctor’s supervision.

Possible Interactions

If you are currently being treated with any of the following medications, you should not use eucalyptus without first talking to your health care provider.

5-Fluorouracil (5-FU) -- In an animal study, using eucalyptus oil on the skin caused more absorption of topical 5-fluorouracil (5-FU), a medication used to treat cancer.

Taking eucalyptus orally may interact with several medications. You should not take eucalyptus by mouth unless under your doctor’s supervision.

Supporting Research

Abdullah D, Ping QN, Liu GJ TI. Enhancing effect of essential oils on the penetration of 5-fluorouracil through rat skin. Yao Hsueh Hsueh Pao. 1996;31(3):214-221.

Ashour HM. Antibacterial, antifungal, and anticancer activities of volatile oils and extracts from stems, leaves, and flowers of Eucalyptus sideroxylon and Eucalyptus torquata. Cancer Biol Ther. 2008 Mar;7(3):399-403.

Biruss B, Kahlig H, Valenta C. Evaluation of a eucalyptus oil containing topical drug delivery system for selected steroil hormones. Int J Pharm. 2007;328(2);142-51.

Cermelli C, Fabio A, Fabio G, Quaglio P. Effect of eucalyptus oil on respiratory bacteria and viruses. Curr Microbiol. 2008;56(1):89-92.

Chen ZZ, Ho CK, Ahn IS, Chiang VL. Eucalyptus. Methods Mol Biol. 2006;344:125-34.

George J, Hegde S, Rajesh KS, Kumar A. The efficacy of a herbal-based toothpaste in the control of plaque and gingivitis: a clinico-biochemical study. Indian J Dent Res. 2009 Oct-Dec;20(4):480-2.

Jaenson TG, Garboui S, Palsson K. Repellency of oils of lemon eucalyptus, geranium, and lavender and the mosquito repellent MyggA natural to Ixodes ricinus (Acari: Ixodidae) in the laboratory and field. J Med Entomol. 2006 Jul;43(4):731-6.

Kehrl W, Sonnemann U, Dethlefsen U. Therapy for acute nonpurulent rhinosinusitis with cineole: results of a double-blind, randomized, placebo-controlled trial. Laryngoscope. 2004;114:738–742.

Kumar A, et al. Antibacterial properties of some Eucalyptus oils. Fitoterapia. 1988;59:141-144.

Osawa K, Yasuda H, Morita H, Takeya K, Itokawa H. Macrocarpals H, I, and J from the Leaves of Eucalyptus globulus. J Nat Prod. 1996;59:823-827.

Sadlon AE, Lamson DW. Immune-modifying and antimicrobial effects of Eucalyptus oil and simple inhalation devices. Altern Med Rev. 2010 Apr;15(1):33-47. Review.

Salari MH, Amine G, Shirazi MH, Hafezi R, Mohammadypour M. Antibacterial effects of eucaluyptus globulus leaf extract on pathogenic bacteria isolated from specimens of patients with respiratory tract disorders. Clin Microbiol Infect. 2006;12(2):194-6.

Sartorelli P, Marquioreto AD, Amaral-Baroli A, et al., Chemical composition and antimicrobial activity of the essential oils from two species of Eucalyptus. Phytother Res. 2006;[Epub ahead of print].

Serafino A, et al. Stimulatory effect of eucalyptus essential oil on innate cell-mediated immune response. BMC Immunol. 2008;9:117.

Swanston-Flatt SK, Day C, Bailye CJ, Flatt PR. Traditional plant treatments for diabetes. Studies in normal and streptozotocin diabetic mice. Diabetologia. 1990;33(8):462-464.

Tesche S, Metternich F, Sonnemann U, et al. The value of herbal medicines in the treatment of acute non-purulent rhinosinusitis : Results of a double-blind, randomised, controlled trial. Eur Arch Otorhinolaryngol. 2008 Apr 25.

Thorsell W, Mikiver A, Tunón H. Repelling properties of some plant materials on the tick Ixodes ricinus L. Phytomedicine. 2006 Jan;13(1-2):132-4.

Webb NJ, Pitt WR. Eucalyptus oil poisoning in childhood: 41 cases in south-east Queensland. J Paediatr Child Health. 1993;29(5):368-371.

Woolf A. Essential oil poisoning. Clin Toxicol. 1999;37(6):721-727.

Alternative Names

Australian fever tree; Blue gum; Eucalyptus globulus; Red gum


Version Info

  • Last Reviewed on 01/02/2011
  • Steven D. Ehrlich, NMD, Solutions Acupuncture, a private practice specializing in complementary and alternative medicine, Phoenix, AZ. Review provided by VeriMed Healthcare Network.

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