What Is It?
From cough cure to tension-reliever, the woody scented oil and leathery leaves of the stately eucalyptus tree have found myriad uses over the centuries. Australian aborigines relied on this native evergreen for soothing painful joints and healing skin lesions. And settlers to the continent dubbed eucalyptus the “fever tree” in recognition of its disease-fighting powers. While these early users ascribed its potency to the tree’s brisk aroma, it is now known that the thirsty roots were responsible: They kept the surrounding ground relatively dry and thus free of malaria-carrying mosquitoes.
Once Europeans were introduced to the eucalyptus tree, they too rapidly recognized its gifts–medicinal and otherwise. In fact they began to rely so heavily on eucalyptus oil for sterilizing medical and surgical equipment that it was briefly referred to as “catheter oil.”
Of the 300 eucalyptus species, the most commonly used medicinally are Eucalyptus globulus and E. fructicetorum. The crucial medicinal compound called eucalyptol (also known as cineole) appears in the oil, which is specially steam-extracted from the leaves and branch tips of these species. Oils of industrial- and perfume-grade quality are typically taken from different eucalyptus species altogether.
One of the most enduring medical uses for eucalyptus–and not surprisingly, one of the best substantiated–is its power to ease nasal congestion and quell cough. In fact, many commercial cough and cold remedies feature small amounts of the potent oil, as do countless chest rubs and pain-relieving lotions. Because it’s so strong, the oil is typically diluted before being placed in these products.
Many uses for eucalyptus have been proposed and tested over the years. One study found that a blend of eucalyptus, peppermint, and ethanol oils could relieve headache-related muscle tension when it was gently rubbed into the forehead and temples. Actual headache pain did not resolve, however. Other research indicates that eucalyptus oil can kill dust mites and fleas–common sources of allergic reactions. The oil is also a natural flea repellent.
Specifically, eucalyptus may help to:
Clear congestion associated with colds, cough, flu, asthma, sinusitis, and croup. When inhaled, eucalyptol, the oil’s key medicinal ingredient, works as an expectorant, loosening sticky mucus and making it easier to cough up and out of the chest. In addition, astringent substances in the oil called tannins tighten and thus soothe mucous membrane inflammation in the mouth, nose, and throat. Lozenges containing eucalyptol increase saliva production, prompting more frequent swallowing and thus reducing the impulse to cough. The oil’s germ-fighting actions may reduce the risk of a secondary respiratory infection.
Control earache pain. When inhaled, a eucalyptus oil steam solution will prompt the eustachian tubes connecting the middle ear and the throat to open. Fluids will more easily drain from the ear as a result, relieving often painful pressure.
Treat cuts and scrapes and other minor wounds. In test tube studies, eucalyptus oil has been shown to fight infection-causing bacteria, fungi, and viruses. This antiseptic action, as well as its anti-inflammatory powers, helps explain the oil’s popularity for treating wounds in the pre-antibiotic era.
Ease arthritis pain and muscle aches. Rubbed into the skin, eucalyptus oil (diluted with a carrier oil) stimulates blood flow and generates a feeling of warmth. Its most important function may be to distract, or mask, underlying discomfort or pain, making it useful for those suffering from arthritis or muscle aches.
Fight gum disease. Most likely because of its germ-fighting properties, eucalyptus appears to inhibit the formation of the sticky film on teeth and gums known as plaque. If allowed to build up over time, plaque will turn into a hard mineral shell called tartar that wears away at gum tissue. In a 1998 Japanese study of 15 people, chewing gum containing eucalyptus proved significantly more effective than a placebo in stopping plaque from forming.
Note: Eucalyptus has also been found to be useful for a number of other disorders. For information on these additional ailments, see our Dosage Recommendations Chart for Eucalyptus.
Not all eucalyptus species provide the medically therapeutic oil; look for products containing at least 70% to 85% eucalyptol (cineole).
Eucalyptus oil should always be diluted before applying it topically or ingesting it; always follow package instructions.
For congestion related to colds, cough, flu, asthma, sinusitis, earache, and other types of respiratory conditions, there are three effective treatment approaches:
–Make a steam inhalation solution. Add a drop of eucalyptus oil (or two or three leaves) to a pan of water. Bring the water to a boil and remove the pan from the heat. Drape a towel over your head and the pan. Close your mouth and inhale the steam deeply through both nostrils. Blow your nose as frequently as necessary. Repeat twice daily, more frequently for earaches.
–Add a drop or two of eucalyptus oil to a commercial steam inhaler. Follow the manufacturer’s instructions.
–Drink two cups of eucalyptus leaf tea daily. Make the tea by pouring one cup (8 ounces) of hot (but not boiling) water over 1 to 2 teaspoons of finely crushed eucalyptus leaves. Steep for 10 minutes, then strain. Alternatively, make the tea with eucalyptus tincture, adding the number of drops designated on the label (typically 30 to 45) to an 8-ounce cup of hot water.
For minor wounds: Clean the wound thoroughly. Mix the diluted eucalyptus oil with an equal quantity of an alcohol-based topical antiseptic and apply a few drops to the affected area. Seek medical attention if signs of infection develop (redness, localized warmth, fever).
For arthritis pain or muscle aches: Rub several drops of well-diluted eucalyptus oil into the skin. Alternatively, soak in an herbal bath made by wrapping a handful of eucalyptus leaves in cheesecloth and allowing the bath water to run through the bundle.
For gum disease: Place a few drops of well-diluted eucalyptus oil onto your fingertip and massage into your gums. Alternatively, purchase a toothpaste containing eucalyptus oil.
Be sure to check out our Dosage Recommendations Chart for Eucalyptus, which lists therapeutic dosages for specific ailments at a glance.
Guidelines for Use
Protect yourself from the oil’s strong fumes by keeping your eyes shut when inhaling any eucalyptus remedy.
There are no known drug or nutrient interactions associated with eucalyptus leaf or oil.
Possible Side Effects
In rare cases, eucalyptus can cause nausea, vomiting, and diarrhea. Consult your doctor if this occurs.
In the small number of people who are allergic to eucalyptus, a topical preparation containing the oil may cause an irritating but relatively harmless rash.
Ingesting even small amounts of undiluted eucalyptus oil can cause serious reactions, including a drop in blood pressure, circulation problems, collapse, suffocation, and death. Commercial products that contain the oil pose this risk as well if ingested in higher-than-recommended amounts. Seek emergency medical care if you suspect an overdose.
When used as recommended, eucalyptus-containing commercial preparations–including eucalyptus tea–are very safe. Still, it’s important to handle eucalyptus oil with extreme care.
Because of its potency, don’t administer any product containing eucalyptus (internal or external) to a small child.
Eucalyptus oil products should never be applied to the face of an infant or small child–especially on or near the nose–because they can cause cause asthma-like reactions. Extreme cases could potentially result in death by asphyxiation.
Don’t take eucalyptus if you have digestive problems, inflammation of the stomach or intestines, a biliary duct disorder, or liver disease.
Pregnant women should not take eucalyptus.
Asthma Breathe in steam made from 1 or 2 drops oil added to pan of near-boiling water or a commercial steam inhaler. Or drink 2 cups tea a day.
Colds Breathe in steam made from 1 or 2 drops oil added to pan of near-boiling water or a commercial steam inhaler. Or drink 2 cups tea a day.
Cough Add a few drops of oil to a pan of hot water; cover your head with a towel and inhale the steam.
Earache Breathe in steam made from 5 or 6 drops oil added to pan of near-boiling water or a commercial steam inhaler. Or drink 2-4 cups of eucalyptus tea a day.
Flu Breathe in steam made from 1 or 2 drops oil added to pan of near-boiling water or a commercial steam inhaler. Or drink 2 cups tea a day.
Gum Disease Massage several drops of commercially diluted oil into your gums with your finger. Or use a toothpaste with eucalyptus oil.
Muscle Aches and Pains Rub several drops of commercially diluted oil into the skin. Or soak in an herbal bath made by running the bath water through a cheesecloth-wrapped handful of eucalyptus leaves.
Sinusitis Breathe in steam made from 1 or 2 drops oil added to pan of near-boiling water or a commercial steam inhaler. Or drink 2 cups tea a day.
David Edelberg, MD