Tea tree essential oil, Melaleuca alternifolia, has gained immense recognition as the strongest anti-fungal, anti-viral and anti-bacterial essential oil. Tea tree essential oil is a popular addition to skin care formulations for its germ-killing properties. It is often used in wintertime cold formulations to keep germs from spreading. It is helpful within acne products and can help fight cold sores and heal wounds. Tea tree essential oil blends well with lavender, peppermint, eucalyptus, niaouli, spikenard, sandalwood and vetiver. Using tea tree oil neat can occasionally cause skin irritation despite the many recommendations for using the oil without dilution.