Ingredient dictionary

Coumarin

Coumarin is a naturally occurring aromatic compound with a sweet, hay-like scent, used mainly to give products a fragrance. It is on the label of 111 products in our library. Checked against our library November 6, 2026.

The catch: coumarin is one of the 26 fragrance allergens the EU requires brands to name on labels, so if you know you react to it, check the list, including products scented only with essential oils.

Labelled fragrance allergens. The 26 scent chemicals the EU makes brands name on the label, such as linalool and limonene.

What Coumarin does

Adds a sweet, hay-like scent
Brings a warm, vanilla-like note
Blends into floral and woody fragrances

Coumarin occurs naturally in plants such as tonka beans, sweet woodruff and some cinnamon varieties. Many perfumers also use a lab-made version, which is the same molecule. Formulators add it to bath, body and hair products mainly for its sweet, hay-like scent with a vanilla-like warmth.

In a formula, coumarin works only as a scent. It does not moisturize, cleanse or condition the skin or hair. Formulators use small amounts and blend it with other fragrance materials to build a warm, soft base. Its effect is on the smell of the product and on people who are sensitive to it.

Good for

Suits people who enjoy sweet, warm, vanilla-like scents in bath, body and hair products, if they have no known fragrance sensitivity.

Frequently asked questions

Is coumarin safe to use?

Many people use coumarin-scented products without any issue. It is a labelled fragrance allergen, so anyone with a known sensitivity should avoid it. Testing a new scented product on a small patch of skin first is sensible.

Is coumarin the same as tonka bean?

No. Tonka bean is a seed that contains coumarin, along with many other compounds. Coumarin is one of the molecules behind tonka's sweet, hay-like smell. Perfumers can use coumarin alone without any tonka bean at all.