1,8-Cineole – PatientsCann UK Skip to main content Back to Terpenes Guide 1,8-Cineole Eucalyptol pronounced: SIN-ee-ol The strong, fresh smell of eucalyptus. Often used to help clear the airways and sharpen focus. Oxygenated monoterpene Boiling point: 176°C Terpene type Oxygenated monoterpene Boiling point 176°C Primary aroma Eucalyptus Key effect Focus Aroma profile How it Smells The aroma of 1,8-Cineole is described as: EucalyptusFreshCoolingMintyCamphor Found naturally in: Eucalyptus, rosemary, sage, bay leaves, tea tree, mugwort Effects Linked Effects Sharpens focusEases breathingAnti-inflammatory These effects are based on early-stage research in animals and cells. They are not proven in humans. Do not change your treatment based on this information. About What is 1,8-Cineole? 1,8-cineole, also called eucalyptol, is the terpene behind the strong, fresh smell of eucalyptus. It has a cool, clearing quality that many people know from chest rubs and cold remedies. It also appears in rosemary, sage and bay leaves. Unlike the pure pine or citrus terpenes, cineole carries an oxygen atom in its structure, which is why it smells so sharp and clean (Booth and Bohlmann, 2019). Effects in detail What the Research Says Cineole is one of the better-studied plant terpenes. Research suggests it may help open the airways and ease breathing, and it is widely used in cough and cold products for this reason (Nuutinen, 2018). Some studies have also looked at whether it may help with focus and clear thinking, and at its anti-inflammatory effects. Even with this longer history, most careful studies are small, so it should not be seen as a treatment on its own. Everyday sources Where You Find it in Daily Life You meet cineole in eucalyptus and tea tree oils, in fresh rosemary and sage, and in bay leaves. It is the main active smell in many vapour rubs, throat sweets and mouthwashes. A word of care: eucalyptus oil is strong and should never be swallowed neat, especially by children. Research Key Studies Nuutinen (2018) reviewed the evidence on cineole, including its use for easing breathing and its anti-inflammatory activity. Its role in the entourage effect alongside cannabinoids has also been discussed (Russo, 2011). Its chemistry, including the oxygen in its structure, is recorded in public databases (National Center for Biotechnology Information, 2025). Previousβ-Pinene NextFenchol Back to full Terpenes Guide Important: The information on this page is for education only. It is not medical advice. Terpene research is still in its early stages. Many studies have been done in animals, not yet in people. Always speak to your doctor before changing your treatment. PatientsCann UK does not recommend any specific cannabis product. References Nuutinen, T. (2018) ‘Medicinal properties of terpenes found in Cannabis sativa and Humulus lupulus’, European Journal of Medicinal Chemistry, 157, pp. 198-228. doi: 10.1016/j.ejmech.2018.07.076. Russo, E.B. (2011) ‘Taming THC: potential cannabis synergy and phytocannabinoid-terpenoid entourage effects’, British Journal of Pharmacology, 163(7), pp. 1344-1364. doi: 10.1111/j.1476-5381.2011.01238.x. Booth, J.K. and Bohlmann, J. (2019) ‘Terpenes in Cannabis sativa: from plant genome to humans’, Plant Science, 284, pp. 67-72. doi: 10.1016/j.plantsci.2019.03.022. National Center for Biotechnology Information (2025) PubChem Compound Database. Bethesda: U.S. National Library of Medicine. Available at: https://pubchem.ncbi.nlm.nih.gov (Accessed: 11 June 2026). Cicada Jersey (2020) Terpene Wheel. Available at: https://cicada.je/terpene-wheel/ (Accessed: 11 June 2026).
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