All the eucalyptus trees – of which there are 600 or so species originate from Australia. They have now been successfully transplanted to many other warm parts of the world, notably Central Asia, North Africa and California (where they have almost become a pest, threatening many native species). Sub-tropical on the whole, there are only a few species which grow well in more northerly areas. They grow very tall and very rapidly – 21-27 m (70-90 ft) in about 20 years – and one tree in Australia is said to be the tallest non-conifer in the world.The evergreen eucalyptus trees are known commonly as gum trees because the bark can exude a sweet-smelling gum. It is the leaves, however, which contain droplets of essential oil, and those of the Tasmanian blue gum, E. globulus, are the most esteemed in therapy. The leaves of young trees are rounded and silvery (those seen in florists’ shops), but these change as the tree matures, to very long ovals, generally of a deep blue-grey-green color. The flowers of the blue gum are like tiny pots from which a lid pops off, with fragrant white flower stamens unfolding.Commercial distillation of eucalyptus oil began in Australia in 1854, and has been continued there and in other countries where the tree has become acclimatized.The first works on the antiseptic and anti-bactericidal properties of the oil were published in Germany by doctors Cloez (1870), Faust and Homeyer (1874). They classified it then as being sudorific, a stimulant, anti-catarrhal, and astringent. It was prescribed for all respiratory system conditions such as bronchitis, flu, asthma and coughs. These properties are still the best known, and many French prescriptions and commercial preparations for colds include eucalyptus in various forms.EUCALYPTUS ESSENTIAL OILDescription: The twigs and leaves of young and more mature trees are distilled for the oil. The more mature trees yield more oil, with better aromatic qualities. The oil has a very fluid consistency, and is a pale clear yellow. Its aroma is fresh, balsamic and agreeable.The principal constituents: Cineol or eucalyptol, from 70 -80 per cent; then there are various aldehydes, ketones, sesquiterpenic alcohols and terpenes. There are approximately 250 different constituents in eucalyptus so it is extremely difficult to reproduce synthetically.USESEucalyptus oil is highly antiseptic, and it is a favorite remedy for colds and flu, coughs, bronchitis, catarrh and viral infections. There are many ways in which it can be used for these ailments.As an inhalation, add 3 drops to a bowl of hot water and inhale for 5 minutes. Do this three to four times a day. Put a few drops on a handkerchief and inhale from time to time.Add a few drops to a warm bath. Make up an oil containing 50 ml (2 fl oz) soya oil, 2 drops wheat germ oil and 15 drops of eucalyptus, and massage torso and abdomen three times a day.The same oil can also help nervous disorders and fatigue, and convalescents. Massage on sacrum area (lower part of the back), solar plexus and top of hands a few times a day. It acts as a stimulant of the nervous system.Rheumatic conditions can benefit from eucalyptus as well (another familiar use of the oil in commerce is as part of embrocations): mix the oil as above, but use 8 drops eucalyptus and 4 drops thyme oil instead of 15 drops eucalyptus.The leaves can also be used therapeutically for colds and flu. Add 15 ml (1 tbsp) dried leaves to 600 ml (1 pint) boiling water and infuse for 10 minutes. Add a little honey if desired, and drink this tisane throughout the day, at least six to eight cups.An infusion of the leaves in hot water can act as a fumigant, either in public rooms or a sickroom.Research revealed hypoglycemic properties in eucalyptus, and it has been prescribed for high blood pressure and diabetes. By drinking infusions of the leaves, the sugar in urine can drop to a normal level.Eucalyptus winter syrupThis is a wonderful stand-by for when colds and flu are about. It is also extremely good for asthmatics20 g (3/4 oz) dried eucalyptus leaves300 ml (1/2 pint) water300 g (11 oz) fructose or honeyPrepare a very strong infusion by boiling the leaves in the water for 10 minutes. Leave to infuse for 20 minutes, then strain and add the fructose or honey. Store in a dark bottle, and take a teaspoon a few times a day when colds threaten.(See also abscesses and boils, asthma, burns, bursitis, chest infections, cuts and wounds, cystitis, fever, hay fever, neuralgia, pneumonia, sinusitis, stiffness and stings and bites.)Other usesThe trees are said to keep insects away. Oil from E. citriodora, the lemon-scented gum (the leaves of which contain citronellol), is used in perfumery, and the leaves in potpourris. Much of the oil produced is used in commerce for products as apparently diverse as disinfectant and boot polish. The bark of some eucalyptus – which is as deciduous as most trees’ leaves – yields a beige dye; the leaves a red dye.