Negative Effects of Tea Tree Oil

Tea tree oil, also known as melaleuca oil, comes from the leaves of the Melaleuca alternifolia. The leaves are processed to extract their natural oils, which are then used in hundreds of products ranging from shampoos and conditioners to antiseptics and acne treatments. Although the use of this oil has increased in popularity, it's still important to understand the possible side effects that can accompany the use of tea tree oil.

Tea tree leaves (Image: Nirian/iStock/Getty Images)

Skin Irritation

One common side effect of tea tree oil is skin irritation, especially if applied to broken or dry areas of the skin. Skin irritation can include stinging, burning redness itching or inflammation. In some cases, full strength tea tree oil can also cause mild to severe rashes to develop on the treated skin. Performing a skin patch test is recommended before applying

Allergic Reaction

Tea tree oil can also cause a mild to severe allergic reaction to those who are allergic to the plant. If you are allergic to ingredients from the same family as tea tree oil, such as cloves, guava, eucalyptus, or allspice, you may be at a greater risk for having an allergic reaction to tea tree oil, states the American Cancer Society. The longer tea tree oil is allowed to sit and age, the more it also has a chance to break down into components that are more likely to cause an allergic reaction. Signs of a mild allergic reaction may include hives, rashes, itching, or congestion. More serious allergic reactions can include the same signs as a mild reaction plus possible cramps, diarrhea, light-headedness, flushing, vomiting, swelling, or life-threatening anaphylaxis.

Hormonal Side Effects

One troubling side effect of tea tree oil is the possible hormonal side effect on young boys who have not yet started puberty. Tea tree oil used at this age may cause problems with increased production of breast tissue in boys in a condition known as prepubertal gynecomastia, states the National Institute of Health.

Ingestion Side Effects

Tea tree oil is sometimes used orally in its diluted state, such as being used as a natural mouthwash for bad breath and oral hygiene. However, tea tree oil is highly toxic when swallowed, especially at full strength. If swallowed, tea tree oil can cause varying side effects ranging from drowsiness, upset stomach, vomiting, nausea and weakness, to coma, hallucinations, blood cell abnormalities, confusion and ataxia which affects muscle coordination and your ability to move voluntary muscles, states the American Cancer Society.


The side effects of tea tree oil on those who are pregnant or lactating are not yet clear. As such, you should talk to your doctor before application, or avoid the use of tea tree oil all together, recommends

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