Applying a 100 percent solution of tea tree oil to the nails two times daily for six months cures toenail fungus in 18 percent of individuals with the infection, according to WebMD. Lower concentrations of the oil are not effective at curing the fungus.
Fifty-six percent those who apply tea tree oil to a nail with a fungal infection can expect some improvement after three months. After six months of applying the oil, 60 percent can expect some improvement. The treatment is comparable to use of a 1 percent solution of clotrimazole, available only by prescription, according to WebMD.
Tea tree oil comes from the leaves of the Melaleuca alternifolia tree. It is mildly irritating to the skin and causes allergic reactions in some people. Because there are reports of tea tree oil toxicity when used orally, Mayo Clinic warns against taking it by mouth; however, when applied topically, it has antiseptic properties and treats infections. Traditional uses include treating fungal infections, including athlete's foot and nail fungus.
While tea tree oil has many uses, Mayo Clinic indicates using the correct dilution factor is important for treating conditions. When applied at the recommended dose and duration, it is likely safe for individuals without allergies to the product.