While more research is needed, tea tree oil applied to the head may help keep lice away and prevent them from feeding on the scalp.

Tea tree oil is made from the leaves of the tea tree plant. Aboriginal people in Australia have used it medicinally for centuries. People around the world continue to use tea tree oil as a remedy for many conditions.

Among other uses, some people believe that tea tree oil can kill lice. But not all experts are convinced. More research is needed before scientists can draw conclusions.

According to the Mayo Clinic, more research is needed to learn how effective tea tree oil is for combating lice. In particular, scientists need to conduct more large well-designed trials.

In the meantime, some early studies suggest that tea tree oil may be useful for treating head lice. For example, one study published in Parasitology Research suggests that it can kill lice in the nymph and adult stages of life. Tea tree oil treatments also reduced the number of lice eggs that hatched.

Another study, published in BMC Dermatology, also found promising results. The investigators used three different products to treat children with head lice, including one that contained tea tree oil and lavender oil.

After their last day of treatment, nearly all of the children who were treated with the tea tree and lavender product were free of lice. The same was true for children who were treated with a product designed to suffocate lice. In contrast, only a quarter of kids treated with pyrethrins and piperonyl butoxide were lice free. Pyrethrins and piperonyl butoxide are common ingredients in anti-lice shampoos.

Another study reported in the International Journal of Dermatology compared botanical and synthetic substances for preventing lice in primary school-age kids. The researchers compared tea tree oil, lavender oil, peppermint, and DEET.

On its own, tea tree oil was the most effective treatment tested. Tea tree oil and peppermint appeared to be most useful for repelling lice. Tea tree oil and lavender were also found to prevent some feeding by lice on treated skin. While the results show some promise, the investigators concluded that none of the treatments were effective enough to endorse.

In addition to preventing and killing lice on skin, some people believe that tea tree oil is useful for removing lice from laundry. But there’s no scientific evidence that this strategy works. More research is needed to learn how tea tree oil may be used to prevent and combat lice outbreaks.

According to the National Center for Complementary and Integrative Health (NCCIH), it’s considered safe for most adults to apply diluted tea tree oil to their skin. But it does pose some risk of side effects.

For example, tea tree oil contains a compound that can irritate your skin. In some people, it may cause an allergic reaction, known as contact dermatitis. Using it repeatedly may also lead to enlarged breast tissue in prepubescent boys. The NCCIH warns that in one study, a young boy developed breast growth after using hair products that contained tea tree oil and lavender oil.

If you decide to use tea tree oil, apply it topically. Never swallow it.

According to the NCCIH, tea tree oil is toxic when swallowed. It can cause drowsiness, disorientation, rash, and loss of muscle control in your arms and legs. At least one person has gone into a coma after drinking tea tree oil.

If you want to use tea tree oil as a lice treatment, you might be wondering how much you should use. The Mayo Clinic reports that no specific dose of tea tree oil has been proven clinically effective.

Some clinical trials have used a dose of 1 to 10 percent tea tree oil in a shampoo or gel formula. The investigators usually apply these mixtures to participants’ skin at least once a day for as long as four weeks. Ask your doctor for more guidance.

Some early studies suggest that tea tree oil may be effective for treating head lice, either alone or when combined with other botanicals, such as lavender oil. But more large-scale studies need to be conducted before experts can recommend tea tree oil as a safe and effective treatment for lice.

If you or someone in your family has lice, discuss different treatment options with your doctor. Talk with them before you try tea tree oil or other alternative remedies. They can help you assess the potential benefits and risks.