Eucalyptus oil is the generic name for distilled oil from the leaf of ''

Eucalyptus ''Eucalyptus'' () is a genus of over seven hundred species of flowering trees, shrubs or mallees in the myrtle family, Myrtaceae. Along with several other genera in the tribe Eucalypteae, including '' Corymbia'', they are commonly known as ...

'', a genus of the plant family

Myrtaceae Myrtaceae, the myrtle family, is a family of dicotyledonous plants placed within the order Myrtales. Myrtle, pōhutukawa, bay rum tree, clove, guava, acca (feijoa), allspice, and eucalyptus are some notable members of this group. All sp ...

native to

Australia Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country by ...

and cultivated worldwide. Eucalyptus oil has a history of wide application, as a

pharmaceutical A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy ( pharmacotherapy) is an important part of the medical field and ...

antiseptic An antiseptic (from Greek ἀντί ''anti'', "against" and σηπτικός ''sēptikos'', "putrefactive") is an antimicrobial substance or compound that is applied to living tissue/skin to reduce the possibility of infection, sepsis, or putre ...

, repellent,

flavouring A flavoring (or flavouring), also known as flavor (or flavour) or flavorant, is a food additive used to improve the taste or smell of food. It changes the perceptual impression of food as determined primarily by the chemoreceptors of the gus ...

fragrance An aroma compound, also known as an odorant, aroma, fragrance or flavoring, is a chemical compound that has a smell or odor. For an individual chemical or class of chemical compounds to impart a smell or fragrance, it must be sufficiently v ...

and industrial uses. The leaves of selected ''Eucalyptus''

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...

are steam distilled to

extract An extract is a substance made by extracting a part of a raw material, often by using a solvent such as ethanol, oil or water. Extracts may be sold as tinctures, absolutes or in powder form. The aromatic principles of many spices, nuts ...

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 China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's List of countries and dependencies by population, most populous country, with a Population of China, population exceeding 1.4 billion, slig ...

produces about 75% of the world trade, but most of this is derived from the cineole fractions of

camphor laurel ''Camphora officinarum'' is a species of evergreen tree that is commonly known under the names camphor tree, camphorwood or camphor laurel. Description ''Camphora officinarum'' is native to China south of the Yangtze River, Taiwan, southern ...

rather than being true eucalyptus oil. Significant producers of true eucalyptus include

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring coun ...

Portugal Portugal, officially the Portuguese Republic ( pt, República Portuguesa, links=yes ), is a country whose mainland is located on the Iberian Peninsula of Southwestern Europe, and whose territory also includes the Atlantic archipelagos of th ...

Spain , image_flag = Bandera de España.svg , image_coat = Escudo de España (mazonado).svg , national_motto = '' Plus ultra'' (Latin)(English: "Further Beyond") , national_anthem = (English: "Royal March") , ...

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the eas ...

, and

Eswatini Eswatini ( ; ss, eSwatini ), officially the Kingdom of Eswatini and formerly named Swaziland ( ; officially renamed in 2018), is a landlocked country in Southern Africa. It is bordered by Mozambique to its northeast and South Africa to its no ...

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

grade.

Rectification Rectification has the following technical meanings: Mathematics * Rectification (geometry), truncating a polytope by marking the midpoints of all its edges, and cutting off its vertices at those points * Rectifiable curve, in mathematics * Recti ...

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 ''Corymbia citriodora'', commonly known as lemon-scented gum and other common names, is a species of tall tree that is endemic to north-eastern Australia. It has smooth white to pink bark, narrow lance-shaped to curved adult leaves, flower buds ...

''). The eucalyptus genus also produces non-cineole oils, including piperitone,

phellandrene Phellandrenes are a pair of organic compounds that have a similar molecular structure and similar chemical properties. α-Phellandrene and β-phellandrene are cyclic monoterpenes and are double-bond isomers. In α-phellandrene, both double bon ...

, citral,

methyl cinnamate Methyl cinnamate is the methyl ester of cinnamic acid and is a white or transparent solid with a strong, aromatic odor. It is found naturally in a variety of plants, including in fruits, like strawberry, and some culinary spices, such as Sichuan p ...

and geranyl acetate.

Uses

Herbal medicine

The

European Medicines Agency The European Medicines Agency (EMA) is an agency of the European Union (EU) in charge of the evaluation and supervision of medicinal products. Prior to 2004, it was known as the European Agency for the Evaluation of Medicinal Products or Eur ...

Committee on Herbal Medicinal Products The Committee on Herbal Medicinal Products (HMPC), is the European Medicines Agency's committee responsible for elaborating the agency's opinions on herbal medicines. Role HMPC aims at assisting in the harmonization of procedures and provisions con ...

concluded that

traditional medicine Traditional medicine (also known as indigenous medicine or folk medicine) comprises medical aspects of traditional knowledge that developed over generations within the folk beliefs of various societies, including indigenous peoples, before the ...

s based on eucalyptus oil can be used for treating

cough A cough is a sudden expulsion of air through the large breathing passages that can help clear them of fluids, irritants, foreign particles and microbes. As a protective reflex, coughing can be repetitive with the cough reflex following three ph ...

associated with the

common cold The common cold or the cold is a viral infectious disease of the upper respiratory tract that primarily affects the respiratory mucosa of the nose, throat, sinuses, and larynx. Signs and symptoms may appear fewer than two days after expos ...

, 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

. Cineole-based eucalyptus oil is used as a flavouring at low levels (0.002%) in various products, including baked goods,

confectionery Confectionery is the Art (skill), art of making confections, which are food items that are rich in sugar and carbohydrates. Exact definitions are difficult. In general, however, confectionery is divided into two broad and somewhat overlappi ...

meat Meat is animal flesh that is eaten as food. Humans have hunted, farmed, and scavenged animals for meat since prehistoric times. The establishment of settlements in the Neolithic Revolution allowed the domestication of animals such as chic ...

products and beverages. Eucalyptus oil has

antimicrobial An antimicrobial is an agent that kills microorganisms or stops their growth. Antimicrobial medicines can be grouped according to the microorganisms they act primarily against. For example, antibiotics are used against bacteria, and antifungals ar ...

activity against a broad range of foodborne human

pathogens In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a ger ...

and food spoilage

microorganisms A microorganism, or microbe,, ''mikros'', "small") and ''organism'' from the el, ὀργανισμός, ''organismós'', "organism"). It is usually written as a single word but is sometimes hyphenated (''micro-organism''), especially in olde ...

. Non-cineole peppermint gum, strawberry gum and lemon ironbark are also used as flavouring. Eucalyptus oil is also used as a

component to impart a fresh and clean aroma in

soap Soap is a salt of a fatty acid used in a variety of cleansing and lubricating products. In a domestic setting, soaps are surfactants usually used for washing, bathing, and other types of housekeeping. In industrial settings, soaps are us ...

detergent A detergent is a surfactant or a mixture of surfactants with cleansing properties when in dilute solutions. There are a large variety of detergents, a common family being the alkylbenzene sulfonates, which are soap-like compounds that are m ...

s, lotions, and

perfume Perfume (, ; french: parfum) is a mixture of fragrant essential oils or aroma compounds (fragrances), fixatives and solvents, usually in liquid form, used to give the human body, animals, food, objects, and living-spaces an agreeable scent ...

s. It is known for its pungent, intoxicating scent. Due to its cleansing properties, Eucalyptus oil is found in mouthrinses to freshen breath.

Industrial

Research shows that cineole-based eucalyptus oil (5% of mixture) prevents the separation problem with

ethanol Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an alcohol with the chemical formula . Its formula can be also written as or (an ethyl group linked to a ...

and

petrol Gasoline (; ) or petrol (; ) (see ) is a transparent, petroleum-derived flammable liquid that is used primarily as a fuel in most spark-ignited internal combustion engines (also known as petrol engines). It consists mostly of organic c ...

fuel A fuel is any material that can be made to react with other substances so that it releases energy as thermal energy or to be used for work. The concept was originally applied solely to those materials capable of releasing chemical energy b ...

blends. Eucalyptus oil also has a respectable

octane rating An octane rating, or octane number, is a standard measure of a fuel's ability to withstand compression in an internal combustion engine without detonating. The higher the octane number, the more compression the fuel can withstand before detonatin ...

and can be used as a fuel in its own right. However, production costs are currently too high for the oil to be economically viable as a fuel. Phellandrene- and piperitone-based eucalyptus oils have been used in

mining Mining is the extraction of valuable minerals or other geological materials from the Earth, usually from an ore body, lode, vein, seam, reef, or placer deposit. The exploitation of these deposits for raw material is based on the econom ...

to separate

sulfide minerals The sulfide minerals are a class of minerals containing sulfide (S2−) or disulfide (S22−) as the major anion. Some sulfide minerals are economically important as metal ores. The sulfide class also includes the selenides, the tellurides, ...

via flotation.

Cleaning

Eucalyptus oil is used in household cleaning applications. It is commonly used in commercial laundry products such as wool wash liquid. It is used as a solvent for removing grease and sticky residue.

Safety and toxicity

If consumed internally at low dosage as a flavouring component or in pharmaceutical products at the recommended rate, cineole-based 'oil of eucalyptus' is safe for adults. However, systemic toxicity can result from ingestion or topical application at higher than recommended doses. In Australia, eucalyptus oil is one of the many

essential oil An essential oil is a concentrated hydrophobic liquid containing volatile (easily evaporated at normal temperatures) chemical compounds from plants. Essential oils are also known as volatile oils, ethereal oils, aetheroleum, or simply as the o ...

s that have been increasingly causing cases of poisoning, mostly of children. In the period 2014-2018 there were 2049 reported cases in

New South Wales ) , nickname = , image_map = New South Wales in Australia.svg , map_caption = Location of New South Wales in AustraliaCoordinates: , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , es ...

, accounting for 46.4% of essential oil poisoning incidents. The probable lethal dose of pure eucalyptus oil for an adult is in the range of 0.05 mL to 0.5 mL/per kg of body weight. Because of their high body-surface-area-to-mass ratio, children are more vulnerable to poisons absorbed transdermally. Severe poisoning has occurred in children after ingestion of 4 mL to 5 mL of eucalyptus oil. Eucalyptus oil has also been shown to be dangerous to domestic cats, causing an unstable gait, excessive drooling, and other symptoms of ill health.

History

Australian Aboriginals use eucalyptus leaf infusions (which contain eucalyptus oil) as a traditional

medicine Medicine is the science and practice of caring for a patient, managing the diagnosis, prognosis, prevention, treatment, palliation of their injury or disease, and promoting their health. Medicine encompasses a variety of health care pr ...

for treating body pains, sinus congestion,

fever Fever, also referred to as pyrexia, is defined as having a temperature above the normal range due to an increase in the body's temperature set point. There is not a single agreed-upon upper limit for normal temperature with sources using val ...

, and colds. Dennis Considen and John White, surgeons on the

First Fleet The First Fleet was a fleet of 11 ships that brought the first European and African settlers to Australia. It was made up of two Royal Navy vessels, three store ships and six convict transports. On 13 May 1787 the fleet under the command o ...

, distilled eucalyptus oil from ''

Eucalyptus piperita ''Eucalyptus piperita'', commonly known as Sydney peppermint and urn-fruited peppermint, is a small to medium forest tree native to New South Wales, Australia. Description It has grey, rough and finely fibrous bark on its trunk, but its branch ...

'' found growing on the shores of

Port Jackson Port Jackson, consisting of the waters of Sydney Harbour, Middle Harbour, North Harbour and the Lane Cove and Parramatta Rivers, is the ria or natural harbour of Sydney, New South Wales, Australia. The harbour is an inlet of the Tasman S ...

in 1788 to treat convicts and marines. Eucalyptus oil was subsequently extracted by early colonists, but was not commercially exploited for some time. Baron

Ferdinand von Mueller Baron Sir Ferdinand Jacob Heinrich von Mueller, (german: Müller; 30 June 1825 – 10 October 1896) was a German-Australian physician, geographer, and most notably, a botanist. He was appointed government botanist for the then colony of Vict ...

, Victorian botanist, promoted the qualities of Eucalyptus as a

disinfectant A disinfectant is a chemical substance or compound used to inactivate or destroy microorganisms on inert surfaces. Disinfection does not necessarily kill all microorganisms, especially resistant bacterial spores; it is less effective than s ...

in "fever districts", and also encouraged

Joseph Bosisto Joseph Bosisto CMG, MLA JP (21 March 1827 – 8 November 1898), was a chemist and politician in colonial Victoria, Australia. Background Bosisto was the son of William Bosisto and Maria née Lazenby, of Cookham, Berkshire, and was born on 21 M ...

, a

Melbourne Melbourne ( ; Boonwurrung/ Woiwurrung: ''Narrm'' or ''Naarm'') is the capital and most populous city of the Australian state of Victoria, and the second-most populous city in both Australia and Oceania. Its name generally refers to a metro ...

pharmacist A pharmacist, also known as a chemist (Commonwealth English) or a druggist (North American and, archaically, Commonwealth English), is a healthcare professional who prepares, controls and distributes medicines and provides advice and instructi ...

, to investigate the commercial potential of the oil. Bosisto started the commercial eucalyptus oil industry in 1852 near

Dandenong Dandenong is a southeastern suburb of Melbourne, Victoria, Australia, about from the Melbourne CBD. It is the council seat of the City of Greater Dandenong local government area, with a recorded population of 30,127 at the . Situated mainl ...

, Victoria, Australia, when he set up a distillation plant and extracted the

from the cineole

chemotype A chemotype (sometimes chemovar) is a chemically distinct entity in a plant or microorganism, with differences in the composition of the secondary metabolites. Minor genetic and epigenetic changes with little or no effect on morphology or anatomy m ...

of '' Eucalyptus radiata''. This resulted in the cineole chemotype becoming the generic 'oil of eucalyptus', and " Bosisto's Eucalyptus Oil" still survives as a brand. French chemist, F. S. Cloez, identified and ascribed the name ''eucalyptol'' — also known as cineole — to the dominant portion of ''E. globulus'' oil. By the 1870s oil from ''Eucalyptus globulus'', Tasmanian blue gum, was being exported worldwide and eventually dominated world trade, while other higher quality species were also being distilled to a lesser extent. Surgeons were using eucalyptus oil as an

during

surgery Surgery ''cheirourgikē'' (composed of χείρ, "hand", and ἔργον, "work"), via la, chirurgiae, meaning "hand work". is a medical specialty that uses operative manual and instrumental techniques on a person to investigate or treat a pa ...

by the 1880s. Eucalyptus oil became an important industry in the box-ironbark forests of Victoria during the post gold-rush era of the 1870s. The oil was often described as Australia's natural wonder and was exported to a growing international market, mostly for medicinal purposes. Eucalyptus oil was in particularly big demand during the global influenza pandemic of 1918-19. A distillation plant was established by the

Forests Commission Victoria The Forests Commission Victoria (FCV) was the main government authority responsible for management and protection of State forests in Victoria, Australia between 1918 and 1983. The Commission was responsible for ″forest policy, prevention an ...

at Wellsford State Forest near Bendigo in 1926. The Principal of the Victorian School of Forestry, Edwin James Semmens, undertook much of the pioneering chemistry into the composition of eucalyptus oil. His steam extraction kilns are in the museum at the school. The Australian eucalyptus oil industry peaked in the 1940s, the main area of production being the central goldfields region of Victoria, particularly

Inglewood Inglewood may refer to: Places Australia *Inglewood, Queensland * Shire of Inglewood, Queensland, a former local government area *Inglewood, South Australia *Inglewood, Victoria *Inglewood, Western Australia Canada * Inglewood, Ontario *Inglewoo ...

; then the global establishment of eucalyptus plantations for

timber Lumber is wood that has been processed into dimensional lumber, including beams and planks or boards, a stage in the process of wood production. Lumber is mainly used for construction framing, as well as finishing (floors, wall panels, w ...

resulted in increased volumes of eucalyptus oil as a plantation by-product. By the 1950s the cost of producing eucalyptus oil in Australia had increased so much that it could not compete against cheaper Spanish and Portuguese oils (closer to European Market therefore less costs). Non-Australian sources now dominate commercial eucalyptus oil supply, although Australia continues to produce high grade oils, mainly from blue mallee (''E. polybractea'') stands.

Species utilised

Commercial cineole-based eucalyptus oils are produced from several species of ''Eucalyptus'': * '' Eucalyptus cneorifolia'' * '' Eucalyptus dives'' * '' Eucalyptus dumosa'' * '' Eucalyptus globulus'' * '' Eucalyptus goniocalyx'' * '' Eucalyptus horistes'' * '' Eucalyptus kochii'' * '' Eucalyptus leucoxylon'' * ''

Eucalyptus oleosa ''Eucalyptus oleosa'', commonly known as the red mallee, glossy-leaved red mallee, acorn mallee, oil mallee or giant mallee, is a tree or mallee that is native to Australia. The leaves were once harvested for the production of cineole based ...

'' * '' Eucalyptus polybractea'' * '' Eucalyptus radiata'' * ''

Eucalyptus sideroxylon ''Eucalyptus sideroxylon'', commonly known as mugga ironbark, or red ironbark is a small to medium-sized tree that is endemic to eastern Australia. It has dark, deeply furrowed ironbark, lance-shaped adult leaves, flower buds in groups of se ...

'' * '' Eucalyptus smithii'' * ''

Eucalyptus tereticornis ''Eucalyptus tereticornis'', commonly known as forest red gum, blue gum or red irongum, is a species of tree that is native to eastern Australia and southern New Guinea. It has smooth bark, lance-shaped to curved adult leaves, flower buds in grou ...

'' * '' Eucalyptus viridis'' Non-cineole oil producing species: * '' Eucalyptus dives'' - phellandrene variant * ''Eucalyptus dives'' - piperitone variant * ''

Eucalyptus elata ''Eucalyptus elata'', commonly known as the river peppermint or river white gum, is a species of medium to tall tree that is endemic to eastern Australia. It has rough, compacted bark on the lower trunk, smooth bark above, lance-shaped to curved ...

'' - piperitone variant * ''

Eucalyptus macarthurii ''Eucalyptus'' () is a genus of over seven hundred species of flowering trees, shrubs or mallees in the myrtle family, Myrtaceae. Along with several other genera in the tribe Eucalypteae, including ''Corymbia'', they are commonly known as eu ...

'' - geranyl acetate * ''

Eucalyptus olida ''Eucalyptus olida'' is a species of small to medium-sized tree that is endemic to a restricted area of New South Wales, Australia. It has rough, flaky and fibrous bark on the trunk and larger branches, lance-shaped to curved adult leaves, flow ...

'' - methyl cinnamate * '' Eucalyptus radiata'' - phellandrene variant * ''

Eucalyptus staigeriana ''Eucalyptus staigeriana'', commonly known as the lemon-scented ironbark, is a species of small ironbark tree that is endemic to the Cape York Peninsula. It has rough ironbark on the trunk and branches, lance-shaped to egg-shaped leaves that sme ...

'' - citral, limonene The former lemon eucalyptus species ''

'' is now classified as ''Corymbia citriodora'', which produces a

citronellal Citronellal or rhodinal ( C10 H18 O) is a mono terpenoid aldehyde, the main component in the mixture of terpenoid chemical compounds that give citronella oil its distinctive lemon scent. Citronellal is a main isolate in distilled oils from the ...

-based oil.

Compendial status

* British Pharmacopoeia

References

External links

Toxicity
Eucalyptus oil profile, Chemical Safety Information from Intergovernmental Organizations

MedlinePlus MedlinePlus is an online information service produced by the United States National Library of Medicine. The service provides curated consumer health information in English and Spanish with select content in additional languages. The site brings ...

, U.S. National Library of Medicine,

U.S. National Institutes of Health The National Institutes of Health, commonly referred to as NIH (with each letter pronounced individually), is the primary agency of the United States government responsible for biomedical and public health research. It was founded in the late 1 ...

evidence-based monograph prepared by the Natural Standard Research Collaboration {{Non-timber forest products Essential oils Eucalyptus Flavors * Disinfectants Non-timber forest products