Last updated on August 20, 2026 · Originally published August 1, 2020
Eugenol is the compound that makes cloves smell like cloves. It is not a terpene, and the reason everyone thinks it is turns out to be the interesting part.
Eugenol appears on terpene lists, in terpene blends, and in articles about cannabis terpenes — including, until now, this one. It has a warm, spicy, clove-like aroma, it turns up in essential oils alongside compounds that genuinely are terpenes, and it behaves much as they do in a bottle.
It belongs to a different chemical family entirely.
What is eugenol, if not a terpene?
Eugenol is a phenylpropanoid, and the distinction is about how the plant builds it rather than what it does once built.
Its chemical name is commonly written as 4-allyl-2-methoxyphenol: a benzene ring carrying a hydroxyl group, a methoxy group and a three-carbon allyl side chain. Its closest structural relatives include isoeugenol and methyl eugenol; anethole, which gives anise its character, estragole in tarragon and cinnamaldehyde in cinnamon belong to the same broader phenylpropanoid family.
Terpenes are assembled from five-carbon isoprene units. A monoterpene is two of them joined together — ten carbons, built through the mevalonate or MEP pathways. Eugenol also has ten carbons, which probably contributes to the confusion, but they arrive by a different route. The shikimate pathway supplies the amino acid phenylalanine; from there, the phenylpropanoid pathway runs through cinnamic acid, coniferyl alcohol and coniferyl acetate, which eugenol synthase converts into eugenol.
The same ten-carbon count, two unrelated construction methods. Our guide to the language of terpenes and terpenoids covers where the boundaries of that family actually sit.
Why does eugenol get filed with the terpenes?
Eugenol gets grouped with the terpenes because almost everything about the finished compound invites the mistake. Its structure identifies it as a phenylpropanoid, and its biosynthesis confirms it — but neither is visible in a bottle.
The most persuasive reason is spatial. A 2008 study of sweet basil examined its peltate glandular trichomes — a secretory structure analogous to the glandular trichomes of cannabis — and found the terpenoid pathway and the phenylpropanoid pathway operating side by side within them. The plant runs both production lines in the same gland.
So eugenol emerges from the same tissue as the terpenes, ends up in the same essential oil, distills under similar conditions, smells like it belongs, and has the same carbon count as a monoterpene. On a gas chromatogram it sits among them quite comfortably, which is part of why terpene panels so often report it alongside compounds it is not related to.
The error is correspondingly widespread. Industry documents, patent filings and terpene supplier catalogues routinely list eugenol as a terpene, often alongside the claim that terpenes and terpenoids are the same thing. Neither is correct, though both are common enough that being wrong here puts you in a large crowd.
What is eugenol actually used for?
Eugenol’s best-established medical use is in dentistry, which is also the application where its activity is least disputed.
Zinc oxide-eugenol cement has been a dental staple for well over a century. Mixing eugenol with zinc oxide produces a material used for temporary fillings, cavity liners, root canal sealers and periodontal dressings. It sets into a workable cement, seals reasonably well, and eugenol contributes both an antibacterial effect and a sedative one on inflamed dental pulp.
That last property is the reason clove oil has a long folk history for toothache, and the reason it remains in some over-the-counter dental preparations. The mechanism is broader than a single receptor: eugenol acts on TRPV1, and also inhibits voltage-gated sodium and calcium currents in dental sensory neurons, which is a more conventional route to local numbing.
Beyond dentistry, eugenol is used as a food flavoring, a fragrance ingredient, and in cosmetics and personal care. Clove oil, which is roughly 70 to 90 percent eugenol, is also used as a fish anesthetic in aquaculture and research.
Is eugenol safe?
Eugenol is permitted as a food flavoring and widely used in fragrance at regulated concentrations. Concentrated clove oil is a different matter and deserves stating plainly.
Eugenol is hepatotoxic in overdose. Ingestion of clove oil by young children is a documented cause of acute liver injury, and the quantities involved are small: one published case involved fulminant liver failure in a 15-month-old after 10 mL of clove oil, roughly two teaspoons. The product is a household one, smells pleasant, and is often stored somewhere accessible.
Like camphor, eugenol is a compound with a genuine therapeutic use and a real toxicity profile. It is also a recognized contact allergen. It appears on the European Union’s fragrance-allergen labelling list for that reason, and dental patients occasionally react to eugenol-containing materials.
How much eugenol is in cannabis?
Cannabis generally contains little eugenol by concentration, but that does not necessarily make it aromatically irrelevant.
Analyses of hydrodistilled hemp essential oils have reported eugenol at roughly 0.1 to 0.2 percent in some genotypes and not detected it in others. In 2025, however, a gas chromatography-olfactometry study of six CBD-rich cultivars found eugenol at a high flavor-dilution factor in specific dried flowers. Eugenol is therefore not a major cannabis volatile, but it may contribute disproportionately to the aroma of some plants — and, being a dried-flower finding, it is subject to the same post-harvest losses as everything else in the volatile fraction.
That distinction — between analytical abundance and odor potency — runs through the same study. Several compounds with high flavor-dilution factors were non-terpenes, including sulfur compounds and p-cresol. Aroma extract dilution analysis does not by itself establish each compound’s contribution to the complete aroma; the authors called for quantitative and aroma-reconstitution work to confirm that.
Beta-caryophyllene is ordinarily far more abundant in cannabis and also occurs in clove oil, but a clove-like note cannot simply be assigned to it. Clove contains both compounds: eugenol is a phenylpropanoid, beta-caryophyllene a sesquiterpene. Their structures and biosynthetic origins place them in different chemical families despite their shared botanical setting.
What does the research actually show?
Outside dentistry, the therapeutic literature is largely laboratory work, with very little controlled evidence in people.
Eugenol has shown antimicrobial, antioxidant and anti-inflammatory activity in cell and animal studies, and a widely cited 2012 review catalogues that work in detail. What the literature does not contain is controlled clinical evidence for most of the claims that circulate. Lists of eugenol’s properties — antiviral, anticancer, antispasmodic, digestive — generally compress preclinical findings and whole-oil results into assertions about the isolated compound.
Its use in dentistry is the exception, and the shape of it is the useful part: a topical application, at a defined concentration, in a specific material, for a narrow purpose.
For the compounds that genuinely define cannabis aroma, and what the research says about each, start with our complete guide to cannabis terpenes.
References
- Koeduka T, Fridman E, Gang DR, et al. Eugenol and isoeugenol, characteristic aromatic constituents of spices, are biosynthesized via reduction of a coniferyl alcohol ester. Proceedings of the National Academy of Sciences. 2006;103(26):10128-10133. doi:10.1073/pnas.0603732103
- Tran TKL, Avellaneda T, André A, et al. The plant of many scents: unraveling the odorant composition of selected CBD hemp cultivars. Journal of Agricultural and Food Chemistry. 2025;73(38):24314-24325. doi:10.1021/acs.jafc.5c07208
- Kamatou GP, Vermaak I, Viljoen AM. Eugenol — from the remote Maluku Islands to the international market place: a review of a remarkable and versatile molecule. Molecules. 2012;17(6):6953-6981. doi:10.3390/molecules17066953
- Pieracci Y, Ascrizzi R, Terreni V, et al. Essential oil of Cannabis sativa L.: comparison of yield and chemical composition of 11 hemp genotypes. Molecules. 2021;26(13):4080. doi:10.3390/molecules26134080
- Park CK, Li HY, Yeon KY, et al. Eugenol inhibits sodium currents in dental afferent neurons. Journal of Dental Research. 2006;85(10):900-904. doi:10.1177/154405910608501005
- Lee MH, Yeon KY, Park CK, et al. Eugenol inhibits calcium currents in dental afferent neurons. Journal of Dental Research. 2005;84(9):848-851. doi:10.1177/154405910508400913
- Janes SEJ, Price CSG, Thomas D. Essential oil poisoning: N-acetylcysteine for eugenol-induced hepatic failure and analysis of a national database. European Journal of Pediatrics. 2005;164(8):520-522. doi:10.1007/s00431-005-1692-1
- Xie Z, Kapteyn J, Gang DR. A systems biology investigation of the MEP/terpenoid and shikimate/phenylpropanoid pathways points to multiple levels of metabolic control in sweet basil glandular trichomes. The Plant Journal. 2008;54(3):349-361. doi:10.1111/j.1365-313X.2008.03429.x
Originally published August 2020. Updated August 20, 2026. The original article described eugenol as a terpenoid and a monoterpenoid; it is neither. Eugenol is a phenylpropanoid, built by a different biosynthetic route from the terpenes it is usually grouped with. This update corrects that classification, adds the dental and safety material, and removes therapeutic claims that the cited sources did not support.
Reviewed by Nani Frenkel, chief editor.
