The Aborigines—native Australians—used the leaves of eucalyptus to help heal wounds and reduce fevers. They also knew that if they were stuck without water in the desert area of Australia known as the Outback, they could dig up some eucalyptus roots, which are filled with water, to have a drink.

Eucalyptus leaves and the oil they produce kill bacteria, and ease breathing difficulties in people with croup, asthma, and bronchitis. It is also used externally for chest congestion, to ease aches and pains, and as a deodorant. Eucalyptus is added to perfume, soap, and some foods and drinks. It's also used as an insect repellent and is added to wax candles and insect sprays. If you have dust mite allergies, you might want to consider adding a few drops of eucalyptus essential oil to your washer the next time you do laundry. Recent research suggests that this greatly reduces the numbers of dust mites, and that will help you breathe easier.

Eucalyptus is native to Australia, where it is the primary food in the diet of koala bears. Today it is grown all over the world, including the United States. There are many species of eucalyptus. Some are the size of an ornamental shrub, and some grow to be giant trees. The type of eucalyptus that is most often used medicinally is called blue gum or Australian fever tree. It can grow as high as 230 feet. Its 4- to 12-inch leaves are dark green and shiny. Its blue-gray bark peels, and under it is a cream-colored bark.

Eucalypus extracts and teas are made from soaking leaf material in an alcohol solution that draws out active components. Some of these active components are called tannins and flavonoids. Leaf essential oil, prepared from steam distillation, is mostly made up of an active component called cineole. It also contains other plant chemicals.

Eucalyptus is available as liquid essential oil, essential oil in ointment form, leaf tincture (solution made from herb and alcohol, or herb, alcohol, and water), crude leaf, and tea. Commercial cough drops, syrups, vaporizer fluid, liniments, toothpaste, and mouthwash may contain eucalyptus oil or its main ingredient, cineole.

Before using the following or any dosages, talk to your healthcare provider and follow his or her instructions.

Pediatric

• Eucalyptus should not be used orally in children; eucalyptus in cough drops should only be given to children over the age of 6 to prevent accidental choking.
• Use of eucalyptus as steam, salve, or chest rub may be appropriate for children. The doses for these uses are similar to those identified below for adults.

Adult

• Eucalyptus leaf as infusion (tea): 1 to 2 g per cup three times per day
• Eucalyptus leaf tincture (for congestion): 1/2 to 1 mL per day
• Oil for topical application (sore joints or chest rub for congestion): Add 30 mL oil to 500 mL lukewarm water
• Eucalyptol: 0.05 to 0.2 mL (1 to 2 drops per cup boiling water) daily
• Eucalyptus oil (for topical application): add 1/2 to 1 mL (15 to 30 drops) of oil to 1/2 cup of carrier oil (sesame, olive, etc.). For inhalation, add 5 to 10 drops of oil to 2 cups boiling water; place towel over head and inhale steam.

Do not use eucalyptus if you are pregnant or breastfeeding.

Eucalyptus oil is not toxic when used outside of the body. It should not be taken internally.

The American Herbal Products Association gives eucalyptus leaf a class 2d safety rating. Class 2d means that there are restrictions to an herb's use. In the case of eucalyptus leaf extracts, people with inflammation of the gastrointestinal tract or bile duct inflammatory disease should not use eucalyptus leaf extract. You also shouldn't use it if you have liver disease. Ask your health care provider if either of these conditions apply to you. You also should avoid taking too much leaf extract. The tannins in it could cause stomachaches or damage your liver or kidneys if taken in large amounts.

Never apply eucalyptus oil to the face or nose of a child under age 2.

In an animal study, topical eucalyptus oil enhanced the absorption of 5-fluorouracil, a medication used to treat cancer that was also applied topically. It is too early to draw conclusions about the usefulness of these findings to humans. Therefore, it would be wise to avoid applying eucalyptus oil topically when using other topical medications.

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