Tea Tree Oil
Other common name(s): Australian tea tree oil, melaleuca oil
Scientific/medical name(s): Melaleuca alternifolia
Tea tree oil is a concentrated plant oil from the leaves of a tree native to Australian coastal areas. The tree is known as Melaleuca alternifolia (or tea tree) and is a member of the myrtle family. The oil is distilled into the air through a steam process and used on the skin as an herbal remedy.
Tea tree oil has been used in Australia for many years to treat skin infections. It holds some potential as a treatment for bacterial and fungal infections of the skin and nails. Available scientific evidence does not support claims that it boosts the immune system. Tea tree oil is toxic when swallowed and it should never be taken internally.
How is it promoted for use?
Proponents believe tea tree oil is an antiseptic and use it to fight germs. It has been used to treat cuts, minor burns, athlete's foot, and insect bites. Some claim it can treat bacterial and fungal skin infections, wound infections, gum infections, acne, head lice, eczema, vaginal yeast infections, colds, pneumonia, and other respiratory illnesses.
Although no one claims tea tree oil can prevent or treat cancer, some proponents claim the oil can boost the immune system. Some herbalists claim that tea tree oil can be used as a "lymphatic recharge" for a "sluggish" lymphatic system. Available scientific evidence does not support these claims.
Household cleaners that contain tea tree oil have also been promoted as alternatives to products that contain cancer-causing chemicals, such as formaldehyde.
What does it involve?
Tea tree oil can be dissolved in water or used at full strength. It is also available in the form of ointments, creams, lotions, and soap. Tea tree oil is often sold in dark glass bottles to prevent light from affecting its potency. When used to treat infections and skin conditions, the oil can be applied directly to the skin in full strength or diluted form using cotton swabs. The oil can also be found in deodorants, shampoos, soaps, antiseptic first-aid creams, cosmetics, and household cleaning products.
Tea tree oil should never be taken internally. For colds and other respiratory illnesses, the oil is added to a vaporizer so that the mist can be inhaled. Drops of the oil can be added to bath water. The oil is sometimes mixed in water as a mouthwash.
What is the history behind it?
The aborigines of Australia were the first to discover the healing properties of tea tree oil thousands of years ago. They treated cuts, burns, and skin infections by crushing the leaves of the tree and applying them to cuts and injuries. In the 1770s, the British explorer Captain Cook observed the native Australians brewing tea from the leaves. He then brewed tea of his own to give to his crew to prevent scurvy. He coined the name tea tree.
In the 1920s, Australian physicians began to use the oil to clean wounds and prevent infections after surgery. They believed it to be more effective than carbolic acid, the antiseptic most used at that time. Average Australians then began to use the oil as a household remedy for skin conditions and fungus infections. During World War II, tea tree oil was included in the first-aid kits given to all Australian soldiers and sailors.
After the discovery of penicillin and other antibiotics in the late 1940s, tea tree oil went out of favor as an antiseptic until the 1980s, when it was discovered that some bacteria were resistant to certain antibiotics, such as methicillin and vancomycin. Today, there is renewed interest in tea tree oil as an alternative to these antibiotics for skin infections.
What is the evidence?
Recent laboratory experiments suggest that tea tree oil holds promise as an antiseptic when used on the skin to kill germs, including those that are resistant to methicillin, vancomycin, and other antibiotics. Other laboratory studies suggest that tea tree oil might be helpful against scabies (skin mites) and some types of fungus. A laboratory study published in 2006 showed that tea tree oil can kill yeasts that cause mouth infections of cancer patients with weakened immune systems. However, the safety and effectiveness of tea tree oil has not been tested in clinical studies of cancer patients with mouth infections, and the fact that tea tree oil is toxic when swallowed seems likely to limit its use in mouth infections. Even though laboratory studies may show promise, further studies are needed to find out whether the results apply to humans.
A few human studies have been done on tea tree oil’s effectiveness in treating various conditions. In studies to determine whether tea tree oil helped fungal toenail infections, it compared well to clotrimazole cream, an older treatment. However, the testing procedure was scientifically somewhat weak. Tests to find out whether tea tree oil helped prevent cold sores showed no benefit, but the tests also had some design flaws that could have affected the results. Tea tree oil has also been tested to see whether it helped mild acne. It was compared to benzoyl peroxide for 3 months, and both groups showed similar improvement by the end of the study. Tests to see whether it cured athlete’s foot showed mixed results. Despite years of use, available clinical evidence does not support the effectiveness of tea tree oil for treating skin problems and infections in humans.
Are there any possible problems or complications?
This substance may not have been thoroughly tested to find out how it interacts with medicines, foods, herbs, or supplements. Even though some reports of interactions and harmful effects may be published, full studies of interactions and effects are not often available. Because of these limitations, any information on ill effects and interactions below should be considered incomplete.
In rare cases, allergic reactions (such as rashes) to tea tree oil can occur. The rashes may be mild and itchy, but severe blistering has been reported as well. The rashes usually improve when the person stops using the oil. Serious allergic reactions are possible -- one medical report described a man who had immediate dizziness and swelling in his throat when tea tree oil was applied to his skin. People who are allergic to other members of the myrtle family (Myrtaceae), such as eucalyptus, guava, clove, or allspice, may be more likely to have an allergic reaction. Those who are sensitive to pine or turpentine may also react to tea tree oil because of chemical similarities between the plants. As tea tree oil ages, it breaks down into substances that are more likely to cause reactions. Using fresher products that have not been exposed to air, light, and heat may cause fewer problems with allergies.
Full strength tea tree oil may cause skin irritation even in people who are not allergic to the oil. These people may have less of a problem with more diluted oils. Some tea tree oil preparations contain other ingredients as well, some of which may cause irritation, allergic reaction, or rash on their own.
There is some evidence that the oil should not be used on burns. Tea tree oil is not recommended for children. Women who are pregnant or breast-feeding should not use this oil.
Tea tree oil is toxic when swallowed. It has been reported to cause drowsiness, confusion, hallucinations, coma, unsteadiness, weakness, vomiting, diarrhea, stomach upset, blood cell abnormalities, and severe rashes. It should be kept away from pets and children. Relying on this type of treatment alone and avoiding or delaying conventional medical care for cancer may have serious health consequences.
More information from your American Cancer Society
The following information on complementary and alternative therapies may also be helpful to you. These materials may be found on our Web site (www.cancer.org) or ordered from our toll-free number (1-800-ACS-2345).
The ACS Operational Statement on Complementary and Alternative Methods of Cancer Management
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Note: This information may not cover all possible claims, uses, actions, precautions, side effects or interactions. It is not intended as medical advice, and should not be relied upon as a substitute for consultation with your doctor, who is familiar with your medical situation.
Last Revised: 11/28/2008