In short
Anethole is the phenylpropene that gives anise, star anise and fennel their sweet licorice smell. trans-Anethole is the isomer used in perfumery and flavours.
What Anethole smells like
Anethole is the sweet licorice-anise molecule, the main constituent of anise, star anise and fennel oils. A forum comparison describes star anise, which is dominated by it, as almost pure anethole, whereas anise seed has woody nuances. Compared with its isomer estragole, it is the sweeter, purer anise; estragole is described as greener, more pungent, more herbal and more bitter.
- Leading note
- Sweet licorice-anise
- Supporting facets
- Warm
- Faint facets
- Fennel-seed herbal
- Character
- Sweet, warm, dense, round
What makes Anethole distinctive
It is anise in its sweetest, purest form — the note behind licorice and pastis.
How Anethole is used
Used in anise, licorice and fougère compositions and widely in flavours and oral care.
Typical role: modifier (used in small amounts to change the character of a blend).
How Anethole differs from similar materials
- Estragole
- Estragole is greener, more pungent and herbal — tarragon and basil; anethole is the sweeter, purer anise. (compared directly by a cited source)
- Canthoxal
- Canthoxal is a transparent, watery anise with basil and fennel; anethole is warmer, denser and sweeter.
- Star Anise Oil
- Star anise oil is mostly anethole, adding limonene, methyl chavicol and anisaldehyde. (compared directly by a cited source)
- Sweet Fennel Oil
- Fennel oil is mostly anethole, with fenchone adding a green, camphoraceous edge. (compared directly by a cited source)
- Dihydroanethole
- Dihydroanethole, the saturated relative, is described as sweet, herbaceous and quite powerful.
An asterisk marks a difference that a cited source states directly. The others compare the published descriptions of each material. Smell varies with grade, supplier and dilution; compare them side by side on blotters before substituting one for another.
Formulation considerations
It solidifies a little below room temperature; warm before weighing.
Identity and classification
- Type
- Aroma chemical
- Origin
- Occurs in nature
- Odour family
- Aromatic / Spicy
- Note position
- Top to heart note
- Physical form at room temperature
- Liquid. Melts at about 21 °C: white crystals when cool, a colourless liquid in a warm room (PubChem: NTP, Merck Index).
- Also known as
- trans-Anethole, Anise camphor
- CAS number
- 4180-23-8
- Molecular formula
- C10H12O
- Molecular weight
- 148.2 g/mol
- IUPAC name
- 1-methoxy-4-[(E)-prop-1-enyl]benzene
The CAS number, formula and molecular weight are taken from PubChem compound 637563, whose own record lists this CAS number; checked 19 October 2026.
Safety and compliance
Hazard classification of the neat substance, as PubChem summarises it, read 26 October 2026. Companies notifying the ECHA C&L Inventory classify it (1,880 reports): H317 may cause an allergic skin reaction (95.3% of reports). 55 of the reports find it does not meet the hazard criteria. A skin sensitiser classification concerns handling the neat material and the dose in a finished product; the IFRA Standards, where they apply, set the limits. Unless it is harmonised, this is the notifiers' own classification, not a binding one.
This page is general information, not a safety assessment or a specification. Confirm identity, composition, IFRA status and allergen content from your supplier's documents for the lot you hold.
Materials it works with
-
Star Anise Oil
Essential oil · Aromatic / Spicy — anise, licorice, sweet, spicy
-
Sweet Fennel Oil
Essential oil · Aromatic / Green — anise, sweet, herbal, green
-
Anisaldehyde
Aroma chemical · Powdery / Floral — anisic, hawthorn, floral, sweet
-
Coumarin
Aroma chemical · Powdery / Fougère — hay, sweet, almond, tobacco
Anethole is also suggested as a partner on the pages for Anise Oil, Dihydroanethole, Estragole and Fenchone.
Used in formulas and accords
Used in 2 published formulas
Anethole is an ingredient in 2 perfume formulas in the Formula & Accord Library.
RUŌOD House Originals
Original compositions by RUŌOD House.
Further reading
Questions about Anethole
Is Anethole natural or synthetic?
The molecule occurs in nature. Commercial Anethole may be made by synthesis or obtained from natural sources, so check the supplier's specification if the distinction matters to you.
What is the CAS number of Anethole?
4180-23-8. It was checked against PubChem on 19 October 2026.
Which published formulas use Anethole?
Anethole is used in 2 published formulas in the RUŌOD Lab Formula & Accord Library: Anise Ink and Myrrh Lantern. Each is listed with a link under "Used in formulas and accords" on this page.
Sources
- PubChem — compound 637563, checked 19 October 2026.
- PubChem — GHS classification (the ECHA C&L Inventory notifications and any harmonised EU entry), read 26 October 2026.
- Premiere Peau — Estragole (comparison with anethole) — published perfumery reference.
- Basenotes — discovering anise (forum) — published perfumery reference.
- Yes We Lab — estragole and anethole — published literature.
- Olfactory profile: the RUŌOD Lab team's synthesis of the published descriptions above, reviewed 24 October 2026. Evidence: more than one published description. Classification and the short description: revision 1. Descriptions of odour are judgement, not measurement.