Tea tree oil is a widely-known essential oil from Australia that has been used for almost a century because of its antiseptic and anti-inflammatory properties. It is said that during World War II, Australian soldiers were supplied with the oil in their gear. It is made up of around 100 ingredients, the most significant ones being terpinen-4-ol (40%), γ-Terpinene (23%) and α-Terpinene (10%), with terpinen-4-ol being the primary active element. Clinical Microbiology Reviews suggests that all components of the oil have some level of activity and all contribute to its effective antibacterial, antiviral and antifungal effects. Among its various uses, it is especially effective as a skin care element that reduces acne.