# Eucalyptus (Eucalyptus globulus) *Blue gum, fever tree, stringy bark tree; *Eucalyptus globulus* Labill.; in pharmacy *Eucalypti folium*, the leaf, and *Eucalypti aetheroleum*, the oil* **Known today as.** *Eucalyptus globulus*, the blue gum of Victoria and Tasmania, which Grieve says reaches 375 feet and ranks among the largest trees in the world. Young trees have broad, stalkless, whitish-green leaves set opposite and flat; after four or five years come sword-shaped, bluish leaves, “alternate and vertical, i.e. with the edges turned towards the sky and earth.” The flower bud wears a cap thrown off as a lid when it opens, whence the Greek name, well-covered. The leaves and the oil distilled from them are the medicines. Kind: Plant Poisoning: Convulsant terpenes (thujone, pinocamphone, camphor) (https://thethinkingpress.org/materia-medica/poisons/convulsant-terpenes) Toxic: yes > **Caution.** The oil is dangerous to small children: the European agency contraindicates it under 24 months because, like other essential oils, cineole can cause spasm of the larynx, and in children with a history of seizures. A 2021 review of 110 published cases found seizures brought on by eucalyptus oil applied to the skin, inhaled, or swallowed, in children and adults. Taken by mouth in excess it can cause vomiting, breathing problems, loss of consciousness, and convulsions; it is not for broken or irritated skin, and it calls for caution in inflamed or ulcerated conditions of the gut. Grieve already warned that in large doses it depresses the nervous system and can stop the breathing. ## What was it used for? An antiseptic oil, above all. Grieve calls the medicinal oil “probably the most powerful antiseptic of its class, especially when it is old,” used as a stimulant and antiseptic gargle, inhaled for asthma, diphtheria, and sore throat, applied freely to the skin in croup, and given in drachm doses in tuberculosis and bronchitis. The trees themselves were planted against malaria: the botanist von Müller first suggested their scented leaves might disinfect fever districts, and in Algeria, Grieve says, a marshy, unhealthy district was made one of the healthiest within five years of planting, chiefly by the drying action of the roots. ## What does modern science say? The European Medicines Agency’s herbal committee accepts the oil as a traditional herbal medicine, “exclusively based upon long-standing use,” for the relief of cough associated with a cold and, rubbed on, for localised muscle pain (monograph of 2024), and the leaf for cough associated with a cold (monograph of 2013). The oil’s chief constituent is 1,8-cineole, also called eucalyptol, given in the leaf report as 54 to 95 per cent of the oil. A 2022 meta-analysis of trials for cough found eucalyptus products safe, but their efficacy “minimal and of uncertain clinical importance.” ## Pharmacognosy and toxicology - **1,8-cineole**: also called eucalyptol, 54 to 95 per cent of the oil **Mechanism.** Cineole, like other essential oils, can cause spasm of the larynx in small children; the oil has brought on seizures, applied to the skin, inhaled, or swallowed. **Standing.** European Union herbal monographs: traditional use, “exclusively based upon long-standing use,” of the oil for cough with a cold and for muscle pain (2024), and of the leaf for cough with a cold (2013). ## What lore surrounds it? Grieve reports that the name *globulus* was said to have been given by the French botanist Labillardière because the waxy fruit resembled a button then worn in France. In the Roman Campagna, she says, the monastery of St. Paolo à la tre Fontana, in one of the most fever-stricken districts, became habitable all the year after eucalyptus was planted in its cloisters about 1870, and the disappearance of mosquitoes near plantations was put down to the drainage of their roots. ## What did the older authorities say? **King’s American Dispensatory.** “The Eucalyptus trees are very numerous in their native country, and constitute an important feature in every landscape.” Most of them exude a resinous substance, “and hence are known to the Australian colonists as ‘gum trees,’” and their leaves, opposite and flat in the young tree, turn their edges to the ground in the old, “thus giving the Eucalyptus a strange appearance.” ## Sources - Grieve, M. *A Modern Herbal*, “Eucalyptus.” As published on botanical.com. - Felter, H. W., & Lloyd, J. U. (1898). *King’s American Dispensatory*, vol. 1, “Eucalyptus.” Internet Archive, kingsamericandis01kinguoft. - European Medicines Agency, Committee on Herbal Medicinal Products. *European Union herbal monograph on Eucalypti aetheroleum (Eucalyptus Oil)*. EMA/HMPC/320292/2023, 20 November 2024. - European Medicines Agency, Committee on Herbal Medicinal Products. *European Union herbal monograph on Eucalypti folium (Eucalyptus leaf)*. EMA/HMPC/892618/2011, 15 April 2013. - European Medicines Agency, Committee on Herbal Medicinal Products. *Assessment report on Eucalypti aetheroleum*. EMA/HMPC/320282/2023, 20 November 2024. - European Medicines Agency, Committee on Herbal Medicinal Products. *Assessment report on Eucalypti folium*. EMA/HMPC/892615/2011, 15 April 2013. - Her L, et al. (2022). Efficacy and Safety of Eucalyptus for Relieving Cough: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. *Journal of integrative and complementary medicine*. PMID 35294302. - Panda PK, et al. (2021). Clinico-laboratory characteristics and outcome of patients with eucalyptus oil-induced/provoked seizures: A case series and systematic review of the published patients. *Tropical doctor*. PMID 34282989. - European Medicines Agency, Committee on Herbal Medicinal Products. *European Union herbal monograph on Eucalypti aetheroleum (Eucalyptus Oil)*. EMA/HMPC/320292/2023, 20 November 2024. - European Medicines Agency, Committee on Herbal Medicinal Products. *Assessment report on Eucalypti folium*. EMA/HMPC/892615/2011, 15 April 2013. - Panda PK, et al. (2021). Clinico-laboratory characteristics and outcome of patients with eucalyptus oil-induced/provoked seizures: A case series and systematic review of the published patients. *Tropical doctor*. PMID 34282989. --- *Eucalyptus.* In *Materia Medica*, edited by B. C. P. Statema. Version 1, revised 2026-10-16. The Thinking Press. https://thethinkingpress.org/materia-medica/eucalyptus Historical description, not medical advice.