Tea tree oil is a powerful disinfectant and useful herbal remedy. Extracted from the leaves of Melaleuca alternifolia, a native tree of New South Wales, it is a clear liquid, strongly aromatic with an odor similar to that of eucalyptus. 

Tea tree oil is a good treatment for fungal infections of the skin, toenails or fingernails - conditions notoriously resistant to treatment, even by strong systemic antibiotics.

Choose products that are 100% pure tea tree oil.

To Treat Athlete's Foot, Ringworm, Jock Itch, Boils:

Paint the oil on affected areas two or three times a day.

Wound Rinse:

A ten-percent solution (about one and a half tablespoons to a cup of warm water) can be used on skin to rinse and clean infected wounds.

Oral Rinse:

A ten-percent solution (about one and a half tablespoons to a cup of warm water) can be used as a mouthwash. DO NOT SWALLOW - tea tree oil is nontoxic topically, do not take it internally.

Vaginal Rinse:

A ten-percent solution (about one and a half tablespoons to a cup of warm water) can also be used as an effective vaginal douche for treatment of both yeast and Trichomonas infections (although some women may find it irritating). 

Source

Dr. Weil "What Can Tea Tree Oil Do For You?"