Eucalyptus Oil

by MedlinePlus

Eucalyptus oil is used commonly as a decongestant and expectorant for upper respiratory tract infections or inflammations, as well as for various musculoskeletal conditions. The oil is found in numerous over-the-counter cough and cold lozenges as well as in inhalation vapors or topical ointments. Veterinarians use the oil topically for its reported antimicrobial activity, which is supported by in vitro and in vivo study. Numerous applications are suggested in the sparse literature on this topic, however there is not sufficient controlled support for any human indication at this time. Other applications include as an aromatic in soaps or perfumes, as flavoring in foodstuffs or beverages, and as a dental or industrial solvent.

Eucalyptus oil contains 70-85% 1,8-cineole (eucalyptol), which is also present in other plant oils. Eucalyptol is used as an ingredient in some mouthwash and dental preparations, as an endodontic solvent, and may possess antimicrobial properties. Listerine® mouthrinse is a combination of essential oils (eucalyptol, menthol, thymol, methyl salicylate), which has been shown to be efficacious for the reduction of dental plaque and gingivitis.

Topical use or inhalation use of eucalyptus oil at low concentrations may be safe, although significant and potentially lethal toxicity has been consistently reported with oral use, and may occur with inhalation use as well. All routes of administration should be avoided in children.

Evidence

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Uses based on scientific evidence

Asthma

Initial research suggests that long-term systemic therapy with 1,8-cineol may decrease the amount of steroids needed in steroid-dependent asthma. Further research is needed to confirm anti-inflammatory and mucolytic activity before this agent can be recommended in upper and lower airway diseases.

Decongestant/expectorant

Although commonly used in non-prescription products, there is inconclusive scientific study of eucalyptus oil or eucalyptol (1,8-cineole, a main chemical constituent of eucalyptus oil) taken by mouth or inhaled as a decongestant/expectorant during colds or upper respiratory tract infections. Better research is necessary before a recommendation can be made.

Dental plaque/gingivitis (mouthwash)

Human studies show promising results using mouthwashes containing several potentially active ingredients, including eucalyptus extract or eucalyptol (1,8-cineole, a main chemical constituent of eucalyptus oil). Although these combination mouthwashes show effectiveness (such as Listerine®), it is not clear that eucalyptus oil by itself is effective or safe for this purpose.

Headache (applied to the skin)

Although eucalyptus has been shown to reduce pain in animal studies, the effectiveness of eucalyptus oil applied to the skin for headache relief has not been supported with reliable human research.

Tick repellant (topical)

Preliminary research shows that Citriodiol® spray, containing eucalyptus, may reduce the number of tick bites and thereby tick-borne infections, although additional studies are warranted

Uses based on tradition or theory

The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

AIDS, Alertness, antibacterial, antifungal, anti-inflammatory, antimicrobial, antioxidant, antiviral, aromatherapy, arthritis, astringent, back pain, bronchitis, burns, cancer prevention, cancer treatment, chronic obstructive pulmonary disease (COPD), cleaning solvent, colds, cough, croup, democididosis, deodorant, diabetes, diarrhea, ear infections, emphysema, fever, flavoring, fragrance, herpes, hookworm, inflammation, inflammatory bowel disease, influenza, insect repellant, leukemia, liver protection, muscle/joint pain (applied to the skin), muscle spasm, nerve pain, onychomycosis, parasitic infection, rheumatoid arthritis (applied to the skin), ringworm, runny nose, scabies, shingles, sinusitis, skin infections in children, skin ulcers, snoring, stimulant, strains/sprains (applied to the skin), tuberculosis, urinary difficulties, urinary tract infection, whooping cough, wound healing.

Dosing

The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.

Standardization

Standardization involves measuring the amount of certain chemicals in products to try to make different preparations similar to each other. It is not always known if the chemicals being measured are the "active" ingredients. Standardization data for eucalyptus is limited. It has been suggested that in order to be effective medicinally, eucalyptus leaf oil must contain 70% to 85% eucalyptol (1,8-cineole).

Adults (18 years and older)

Applied to skin: Application of 5% to 20% in an oil-based formulation or 5% to 10% in an alcohol-based formulation has been used. In one study, topical lemon eucalyptus extract spray (Citriodiol®) was applied daily for 2 weeks to the lower extremities to reduce tick attachment.

Inhaled: Tincture with 5% to 10% eucalyptus oil or a few drops placed into a vaporizer as an inhalant have been used.

By mouth: Eucalyptus oil should be taken with caution, since small amounts of oil taken by mouth have resulted in severe and deadly reactions. For eucalyptus oil, doses of 0.05 to 0.2 milliliters or 0.3 to 0.6 grams daily have been used traditionally, but may cause toxic side effects. For infusions prepared with eucalyptus leaf, a quantity of 2 to 3 grams of eucalyptus leaf in 150 milliliters of water, three times a day, has been used traditionally, but may result in toxic side effects.

Mouthwash: Eucalyptol (1,8-cineole) is a major chemical in eucalyptus oil, and it is used in some commercially sold mouthwashes.

Children (younger than 18 years)

Severe side effects have been reported in children after small doses of eucalyptus have been taken by mouth or applied to the skin. Eucalyptus is not recommended for use by infants and young children, especially near the face and nose.

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