Tea tree oil. Close-up of a bottle of tea tree essential oil. This is an oil widely used in aromatherapy. Essential oils are extracted from the flowers, fruits, leaves, roots, seeds and bark of many plants. Essential oils impart flavour and delicate aroma to coffee, teas, wines and liquors and are used in the manufacture of perfumes, soaps and disinfectants. Many also have important medicinal uses. Tea tree oil has antiseptic properties, and is said to cleanse the skin. It is used in the alternative treatment of colds and sore throats. Oils are generally inhaled directly or added to baths to aid relaxation.