Tea tree oil is an oil made from steaming the leaves of a tree that grows in Australia. Other names for tea tree oil are melaleuca oil or tea tree essential oil.

People may put tea tree oil on their skin to treat a variety of conditions. It's believed that tea tree oil kills germs and fungi. Some ways people use tea tree oil include to treat acne, athlete's foot, lice, nail fungus and insect bites.

Tea tree oil is available as an oil. Companies may add it to skin care products, such as soaps, creams, body washes and lotions. Avoid swallowing tea tree oil. The oil can make you very sick if you eat it.

Research on tea tree oil use for specific conditions shows:

• Acne. Research suggests that putting a gel that has 5% tea tree oil in it might help relieve acne. Tea tree oil may irritate the skin less than other acne treatments such as benzoyl peroxide. However, tea tree oil may not work as fast as benzoyl peroxide can.
• Dandruff. Research has not shown that tea tree oil will definitely treat dandruff. A shampoo that has 5% tea tree oil in it that was used for four weeks helped treat dandruff in one study.
• Athlete's foot. A tea tree oil cream, applied twice a day for one month, may relieve some symptoms of athlete's foot. The cream doesn't seem to work as well as antifungal medicines.
• Lice. Tea tree oil alone or combined with lavender oil has shown some promise in treating lice. Standard medicines have been better studied and are thought to work better.
• Nail fungus. Research hasn't shown tea tree oil is effective in treating toenail fungus. One small study found that pure tea tree oil helped a small amount of people who used it to treat toenail fungus. But other studies on using lower amounts of tea tree oil haven't found it helps treat toenail fungus. Tea tree oil may work well when used with other antifungal medicines.
• Mite infections. Smaller research studies suggest that topical tea tree oil may treat a mite infection that occurs on the lower eyelids, called ocular demodicosis. Using tea tree oil wipes for the eyelids may be less irritating than scrubs for the eyes. More studies are needed.
• Dental plaque. Brushing the teeth and then using a mouthwash with a small amount of tea tree oil afterward may lessen dental plaque. Some people may report burning as a side effect.

The way tea tree oil is prepared can vary. A person's results may be different based on how the tea tree oil is made and how much of it is in the product.

Most people can use tea tree oil on their skin with no problems. However, tea tree oil can cause:

• Skin irritation.
• Allergic skin rash, also called dermatitis.
• Itching.
• Stinging.
• Burning.
• Dryness.

Don't use tea tree oil if you have eczema or very sensitive skin. The tea tree oil can irritate your skin.

Tea tree oil is toxic when taken by mouth. Serious side effects can happen, such as:

• Confusion.
• Problems with muscle control and movement, called ataxia.
• Problems breathing.
• Higher white blood cell count.
• A deep state of sleep where a person doesn't respond, called coma.

One small case report found that applying lavender oil and tea tree oil might have led to swelling of the breast tissue, also known as gynecomastia, in a young boy. Researchers don't know if lavender oil or tea tree oil was the cause.

Tea tree oil isn't known to cause interactions with medicines or supplements.