1,8-Cineole – PatientsCann UK

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).

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

  1. 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.
  2. 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.
  3. 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.
  4. 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).
  5. Cicada Jersey (2020) Terpene Wheel. Available at: https://cicada.je/terpene-wheel/ (Accessed: 11 June 2026).