What is oud?
Reviewed by Lucy Grant, co-owner and fragrance reviewer — 24 September 2026
What is oud?
Oud is agarwood: the dark, fragrant resin that forms inside Aquilaria trees after they are wounded and infected by fungi. It is used in perfume, incense and traditional medicine.
- Warm, sweet and woody. A 2022 review links burning agarwood's warm, balsamic smell to rare chromone molecules.
- Few trees make it. Two reviews put resin formation at roughly one Aquilaria tree in ten.
- The trees are protected. All known Aquilaria species are listed under CITES, which restricts the trade.
- Mostly a base note. Oud is in the base of 109 of the 149 house pyramids naming it.
Look up the notes any house publishes in Sentia — free.
Where it comes from
A tree's answer to an injury
Oud is one of several names for agarwood, along with eaglewood, aloeswood and gaharu. It is the resin-filled heartwood of Aquilaria trees, a genus in the Thymelaeaceae family, and it comes from a few pockets of South and Southeast Asia.
- 1The tree is wounded naturally, by insects, or on purpose by growers.
- 2Fungi get in through the open wound.
- 3The tree fights back by filling the wood around the wound with resin.
- 4The wood turns dark and fragrant. That darkened wood is agarwood.
Most trees never get that far. One review estimates that only about 10% of wild Aquilaria form the resin, and another reports 7 to 10% on plantations. The only way to be sure a tree holds it is to cut the tree down, which is part of why wild stands have been logged so hard.
From Shivanand et al., Molecules (2022) and Naziz, Das & Sen, Frontiers in Plant Science (2019), two peer-reviewed reviews whose full texts we read on PubMed Central on 15 September 2026.
The smell
What oud smells like, molecule by molecule
There is no single oud smell to point at. The 2019 review counts some 150 fragrant molecules in agarwood, and they fall into families that chemists describe quite differently:
| Compound family | How it is described |
|---|---|
| 2-(2-Phenylethyl)chromones | Warm, balsamic, long-lasting sweetness in burning agarwood |
| Eudesmanes (selinanes) | Sweet, woody, honey, balsamic, minty, fresh floral |
| Agarospiranes (vetispiranes) | Spicy, peppery, woody, sweet, balsamic |
| Guaianes | Woody and floral |
| Eremophilanes (valencanes) | Warm woody and minty |
| Acoranes | Credited with the long-lasting part of the smell |
Read the right-hand column top to bottom and you have the honest answer to “what does oud smell like”: woody and balsamic at the core, sweet, with spice, pepper and even a minty edge depending on which molecules dominate a given piece of wood.
Counted
How houses use oud in a pyramid
In Sentia’s catalogue, 149 of the 1,038 three-tier pyramids name oud or agarwood, across 21 houses. It sits where the 2019 review says Middle Eastern perfumery uses the oil, at the base.
| Note | Top | Heart | Base |
|---|---|---|---|
| Oud / agarwood149 pyramids | 15% | 27% | 73% |
Its company
What houses put next to it
The note most tied to oud is saffron. It appears in 44% of pyramids that name oud and in 13% of pyramids overall. Rose is next (54% against 32%), then amber (42% against 25%) and incense or frankincense (26% against 13%).
Some notes are less likely beside it. Jasmine turns up in 15% of oud pyramids against 28% overall, and bergamot in 27% against 32%.
- Saffron44%13%
- Rose54%32%
- Amber42%25%
- Patchouli42%29%
- Frankincense / incense26%13%
- Leather18%10%
- Sandalwood37%30%
How houses write it on the label
Across 174 mentions, houses mostly write plain “Oud” or “Agarwood”, and 18 of them name a country, such as Cambodian, Indonesian or Laos oud. Only 7 carry the word “accord”.
- Oud ×101
- Agarwood ×20
- Cambodian Oud ×7
- Oud Accord ×5
- Oud Wood ×5
- Indonesian Oud ×4
- Aoud ×3
- Indian Oud ×3
- Laos Oud ×2
- Cashmere Oud ×2
- Mesmerizing Oud ×2
- Oud Oil ×2
- Oud Wood Accord ×2
None of that proves what is in the bottle. Only 4 mentions, such as “Oud Oil” or “Agarwood essence”, even point to a material rather than a smell, and a label is still the house’s own wording, not a test.
Why it costs what it does
The 2019 review gives agarwood prices from US$100 to US$100,000 a kilogram, depending on the resin and the grade, and calls agarwood oil the most precious essential oil in the world, at up to US$50,000 to US$80,000 a litre. The 2022 review quotes different figures, and the 2019 authors note that reliable data on the trade is not readily available. Treat any single number as a range, not a price list.
Do you actually reach for it?
If an oud bottle is one of the pricier ones on your shelf, it is the one most worth watching. Add what you paid, log each wear, and Sentia works out what every wear has cost.
The notes pages are free, and so are the first 3 bottles you put on your shelf.
Questions
Still wondering
- What does oud smell like?
- Agarwood holds about 150 fragrant molecules, so there is no single answer. Chemists describe its main groups as sweet, woody, balsamic, spicy, peppery and in places minty, with rare chromones behind the warm, sweet smell of the burning wood. In house pyramids it sits most often beside rose, and saffron turns up with it more than three times as often as it does elsewhere.
- Is oud the same as agarwood?
- Yes. Oud, agarwood, eaglewood, aloeswood and gaharu are names for the same resin-filled heartwood of Aquilaria trees.
- Why is oud so expensive?
- Only around one tree in ten forms the resin, the trees take years to do it, and wild Aquilaria are protected. A 2019 review gives prices from US$100 to US$100,000 per kilogram of wood depending on quality, and up to US$50,000 to US$80,000 per litre of oil.
- Does a perfume with oud on its notes list contain real agarwood?
- A notes list cannot prove it. It names a smell, and few houses say on the list where their oud comes from. The same 2019 review warns that fake and adulterated wood is sold as agarwood.