Eucalyptus oil (E. globulus Labillardiere, E. fructicetorum F. Von Mueller, E. smithii R.T. Baker)
  
Eucalyptus oil (E. globulus Labillardiere, E. fructicetorum F. Von Mueller, E. smithii R.T. Baker)
Background
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.
Synonyms
Australian fever tree leaf, blauer gommibaum, blue gum, catheter oil, cineole, 1,8-cineole, essence of eucalyptus rectifiee, essencia de eucalipto, eucalypti aetheroleum, eucalypti folium, eucalyptol, Eucalyptus polybractea , eucalytpo setma ag, fevertree, gommier bleu, gum tree, kafur ag, malee, myrtaceae, oleum eucalypti, schonmutz, southern blue gum, Tasmanian blue gum.
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 evidenceGrade*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.
C
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.
C
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.
C
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.
C
* Key to grades
A: Strong scientific evidence for this use;
B: Good scientific evidence for this use;
C: Unclear scientific evidence for this use;
D: Fair scientific evidence against this use (it may not work);
F: Strong scientific evidence against this use (it likely does not work).
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.
Alertness, AIDS, antibacterial, antifungal, antiviral, aromatherapy, arthritis, astringent, back pain, bronchitis, burns, cancer prevention, chronic obstructive pulmonary disease (COPD), cleaning solvent, colds, cough, croup, deodorant, diabetes, diarrhea, ear infections, emphysema, fever, flavoring, fragrance, herpes, hookworm, inflammation, inflammatory bowel disease, influenza, insect repellant, liver protection, muscle/joint pain (applied to the skin), muscle spasm, nerve pain, parasitic infection, rheumatoid arthritis (applied to the skin), ringworm, runny nose, 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.
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.
Safety
The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.
Allergies
Case reports describe allergic rash after exposure to eucalyptus oil, either alone or as an ingredient in creams. One child developed a rash after taking eucalyptus oil by mouth. Reports also describe hives after exposure to eucalyptus pollen.
Side Effects and Warnings
Severe and potentially deadly side effects are reported with the use of eucalyptus oil by mouth in children and adults. These include slowing of the brain and central nervous system, drowsiness, seizures, and coma. Use caution if driving or operating heavy machinery. Anecdotal reports suggest that serious side effects can develop with as little as one teaspoon taken by mouth. Reports also suggest that inhaled eucalyptus products or bathtub exposure can cause symptoms. Avoid eucalyptus products in infants and young children, as reports describe severe reactions after exposure by mouth or by application to the skin. Ingestion by children of vaporizer formulas containing eucalyptus has been reported.
Symptoms reported with eucalyptus oil taken by mouth include abdominal pain, nausea, vomiting, diarrhea, dizziness, muscle weakness, constricted pupils, a feeling of suffocation or difficulty breathing, wheezing, cough, blue discoloration of the lips or skin, delirium, or convulsions. Drowsiness, hyperactivity, difficulty walking, muscle weakness, slurred speech, fever, pneumonia, and headache have also been reported. Case reports describe several abnormalities in heart function after eucalyptus oil is taken by mouth, including abnormal rhythms, loss of heartbeat, low blood pressure, and complete disruption of the heart and circulation. Individuals with seizure disorder, heart disease, disorders of the stomach or intestines, or lung disease should use caution.
Published reports describe "attacks" in patients with acute intermittent porphyria (AIP), an inherited disorder affecting the liver and blood. Individuals with AIP should avoid eucalyptus products. Other case reports mention symptoms in individuals who have kidney or liver disease or who are taking other medications that are processed by the liver. Eucalyptus is reported to lower blood sugar in diabetic animals, although reliable human studies are not available in this area. Nonetheless, caution is advised in patients with diabetes or hypoglycemia, and in those taking drugs, herbs, or supplements that affect blood sugar. Serum glucose levels may need to be monitored by a healthcare provider, and medication adjustments may be necessary.
Pregnancy and Breastfeeding
Due to the known side effects of eucalyptus, and the unknown effects during pregnancy or breastfeeding, eucalyptus should be avoided by pregnant and breastfeeding women.
References
1. Darben T, Cominos B, Lee CT. Topical eucalyptus oil poisoning. Australas J Dermatol 1998;39(4):265-267.
2. Hindle RC. Eucalyptus oil ingestion. N Z Med J 1994;107 (977) :185-186.
3. Juergens UR, Dethlefsen U, Steinkamp G, et al. Anti-inflammatory activity of 1.8-cineol (eucalyptol) in bronchial asthma: a double-blind placebo-controlled trial. Respir Med 2003;97(3):250-256.
4. Schaller M, Korting HC. Allergic airborne contact dermatitis from essential oils used in aromatherapy. Clin Exp Dermatol 1995;20(2):143-145.
5. Tascini C, Ferranti S, Gemignani G, et al. Clinical microbiological case: fever and headache in a heavy consumer of eucalyptus extract. Clin Microbiol Infect 2002;8(7):437,445-446.
6. Tibballs J. Clinical effects and management of eucalyptus oil ingestion in infants and young children. Med J Aust 1995;163(4):177-180.
7. Tovey ER, McDonald LG. A simple washing procedure with eucalyptus oil for controlling house dust mites and their allergens in clothing and bedding. J Allergy Clin Immunol 1997;100(4):464-466.
8. Webb NJ, Pitt WR. Eucalyptus oil poisoning in childhood: 41 cases in south-east Queensland. J Paediatr Child Health 1993;29(5):368-371.
January 01, 2004 
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