Evidence
Scientists have studied eucalyptus oil for the following health problems:
Decongestant
Eucalyptus oil and eucalyptol (1,8-cineole, a main chemical in eucalyptus oil) are often added to nonprescription decongestant products. However, there is limited scientific study of eucalyptus oil or eucalyptol taken by mouth or inhaled as a decongestant during colds or upper respiratory tract infections. Better research is necessary to make a clear recommendation.
Dental plaque, gingivitis
There is promising research supporting the use of mouthwashes that contain eucalyptus extract or eucalyptol in addition to other ingredients (for example, Listerine). However, it is not known if eucalyptus oil by itself is effective or safe for this use.
Headache
Several animal studies report that eucalyptus applied to the skin can reduce pain. However, there is no reliable research in humans to support the effectiveness of eucalyptus oil applied to the skin for headache pain relief.
Unproven Uses
Eucalyptus oil has been suggested for many other uses, based on tradition or on scientific theories. However, these uses have not been thoroughly studied in humans, and there is limited scientific evidence about safety or effectiveness. Some of these suggested uses are for conditions that are potentially very serious and even life-threatening. You should consult a health care provider before using eucalyptus oil for any unproven use.
AIDS
Arthritis
Asthma
Astringent
Athlete's foot
Burns
Colds
Cough
Croup
Deodorant
Diarrhea
Ear infections
Emphysema and bronchitis
Fever
Flu (influenza virus)
Headache
Inflammatory bowel disease
Insect repellant
Muscle painMuscle spasm
Nerve pain
Parasite infections
Rheumatoid arthritis
Ringworm
Shingles
Sinusitis
Skin infections
Skin ulcers
Snoring
Sprains and strains
Stimulant
Tuberculosis
Urinary retention
Urinary tract infection
Virus infections
Whooping cough
Wound healing
Unproven Uses
Eucalyptus oil has been suggested for many other uses, based on tradition or on scientific theories. However, these uses have not been thoroughly studied in humans, and there is limited scientific evidence about safety or effectiveness. Some of these suggested uses are for conditions that are potentially very serious and even life-threatening. You should consult a health care provider before using eucalyptus oil for any unproven use.
AIDS
Arthritis
Asthma
Astringent
Athlete's foot
Burns
Colds
Cough
Croup
Deodorant
Diarrhea
Ear infections
Emphysema and bronchitis
Fever
Flu (influenza virus)
Headache
Inflammatory bowel disease
Insect repellant
Muscle painMuscle spasm
Nerve pain
Parasite infections
Rheumatoid arthritis
Ringworm
Shingles
Sinusitis
Skin infections
Skin ulcers
Snoring
Sprains and strains
Stimulant
Tuberculosis
Urinary retention
Urinary tract infection
Virus infections
Whooping cough
Wound healing
Potential Dangers
Allergies
There are several reports of allergic skin reactions occurring in people using eucalyptus oil products on their skin. Laboratory tests have shown that people with asthma or other allergies may be more likely to have a reaction to eucalyptus.
Side Effects
Eucalyptus should not be taken by mouth unless under the careful supervision of a licensed health care professional. There have been numerous cases of toxicity with oral use, including vomiting, stomach pains, seizures, abnormal heart rhythms, bleeding, coma and death.
In animals, eucalyptus oil has been shown to lower blood sugar levels. It is not clear if these effects occur in humans.
When used on the skin, rashes and burning have been reported.
When used in baths or as aromatherapy, prolonged use has caused difficulty breathing, drowsiness and dizziness. Skin irritation has also been reported.
Pregnancy And Breast-Feeding
All forms of eucalyptus oil should be avoided by pregnant or breast-feeding women because of its known toxicity. It is not clear if eucalyptus oil is passed to babies through breast milk, but there have been cases of infant deaths from taking eucalyptus oil by mouth.
Interactions
Interactions with drugs, supplements and other herbs have not been thoroughly studied. The interactions listed below have been reported in scientific publications. If you are taking prescription drugs, speak with your health care provider or pharmacist before using herbs or dietary supplements.
Interactions With Drugs
Eucalyptus oil taken by mouth, applied to the skin or used as aromatherapy may increase the amount of drowsiness caused by some drugs. Examples include benzodiazepines, such as lorazepam (Ativan); barbiturates, such as phenobarbital; narcotics, such as codeine; and alcohol. Caution is advised while driving or operating machinery. There is evidence that eucalyptus may interfere with the way the liver breaks down certain drugs. As a result, eucalyptus may cause the levels of these drugs in the body to be too high, leading to serious side effects.
In animals, eucalyptus oil has been shown to lower blood sugar levels. Caution is advised if you are also taking drugs that may lower blood sugar levels. Patients taking oral drugs for diabetes or using insulin should be monitored closely by their health care provider while taking eucalyptus oil. Dosing adjustments may be necessary. Use of aromatherapy for long periods of time may also cause this reaction. The drug 5-fluorouracil may be more absorbed through the skin when applied with eucalyptus oil. If you are taking 5-fluorouracil for a skin condition, speak with your health care provider or pharmacist before you also use eucalyptus oil.
Interactions With Herbs And Dietary Supplements
Eucalyptus oil taken by mouth, applied to the skin or used as aromatherapy may increase the amount of drowsiness caused by some herbs or supplements, such as valerian. Caution is advised while driving or operating heavy machinery. Eucalyptus oil may lower blood sugar levels. Oral use or use as aromatherapy for long periods of time should be avoided in people taking other agents that lower blood sugar levels, such as bitter melon (Momordica charantia). In theory, eucalyptus oil may increase the blood levels of herbs broken down by the liver, such as chasteberry (Vitex agnus-castus). Eucalyptus oil may increase the effects of plants that contain chemicals called pyrrolizidine alkaloids, such as comfrey (Symphytum officinale).
Dosing
The doses listed below are based on scientific research, publications or traditional use. Because most herbs and supplements have not been thoroughly studied or monitored, safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients even within the same brand. Combination products often contain small amounts of each ingredient and may not be effective. Appropriate dosing should be discussed with your health care provider before starting therapy; always read the recommendations on a product's label. The dosing for unproven uses should be approached cautiously, because scientific information is limited in these areas.
Eucalyptus should not be taken by mouth, except under the supervision of a licensed health care professional. Fatal reactions have been reported.
Adults (Aged 18 Or Older)
Aromatherapy or inhalation: A common dose is two to four drops of eucalyptus oil in a vaporizer or a tincture containing 5 percent to 10 percent eucalyptus oil.
On the skin: A common dose is an oil-based formula containing 5 percent to 20 percent eucalyptus or an alcohol-based formula containing 5 percent to 10 percent. Concentrations higher than this may cause skin irritation. Always read product labels.
Children (Younger Than 18)
Eucalyptus oil should not be given to young children or infants in any form (including aromatherapy) because of reports of severe reactions. For older children, use should only be under the supervision of a licensed health care professional.