Eucalyptus oil is the generic name for distilled oil from the leaf of Eucalyptus, a genus of the plant family Myrtaceae native to Australia and cultivated worldwide. Eucalyptus oil has a history of wide application, as a pharmaceutical, antiseptic, repellent, flavouring, fragrance and industrial uses. The leaves of selected Eucalyptus species are steam distilled to extract eucalyptus oil. Types and production Eucalyptus oils in the trade are categorized into three broad types according to their composition and main end-use: medicinal, perfumery and industrial. The most prevalent is the standard cineole-based "oil of eucalyptus", a colourless mobile liquid (yellow with age) with a penetrating, camphoraceous, woody-sweet scent. China produces about 75% of the world trade, but most of this is derived from the cineole fractions of camphor laurel rather than being true eucalyptus oil. Significant producers of true eucalyptus include South Africa, Portugal, Spain, Brazil, Australia, Chile, and Eswatini. Global production is dominated by Eucalyptus globulus. However, Eucalyptus kochii and Eucalyptus polybractea have the highest cineole content, ranging from 80 to 95%. The British Pharmacopoeia states that the oil must have a minimum cineole content of 70% if it is pharmaceutical grade. Rectification is used to bring lower grade oils up to the high cineole standard required. In 1991, global annual production was estimated at 3,000 tonnes for the medicinal eucalyptus oil with another 1500 tonnes for the main perfumery oil (produced from Eucalyptus citriodora). The eucalyptus genus also produces non-cineole oils, including piperitone, phellandrene, citral, methyl cinnamate and geranyl acetate. Uses Herbal medicine The European Medicines Agency Committee on Herbal Medicinal Products concluded that traditional medicines based on eucalyptus oil can be used for treating cough associated with the common cold, and to relieve symptoms of localized muscle pain. Repellent and biopesticide Cineole-based eucalyptus oil is used as an insect repellent and biopesticide. In the U.S., eucalyptus oil was first registered in 1948 as an insecticide and miticide. Flavouring and fragrance Eucalyptus oil is used in flavouring. Cineole-based eucalyptus oil is used as a flavouring at low levels (0.002%) in various products, including baked goods, confectionery, meat products and beverages. Eucalyptus oil has antimicrobial activity against a broad range of foodborne human pathogens and food spoilage microorganisms.<ref>Zhao, J., Agboola, S., Functional Properties of Australian Bushfoods - A Report for the Rural Industries Research and Development Corporation, 2007, RIRDC Publication No 07/030</ref> Non-cineole peppermint gum, strawberry gum and lemon ironbark are