Oud (Agarwood): A Reference Guide to Its Formation, Types, Oil and Trade

In short: Oud (agarwood) is an aromatic wood from trees of the genera Aquilaria and Gyrinops. A healthy tree does not produce this scent; the aromatic resin forms in its wood after a wound or an infection. This is rare in the wild, so it is now induced in cultivated trees, and its quality varies with the method. It is sold as pieces for burning, oud oil is distilled from it, and its grades and prices vary widely. The species of both genera are listed in Appendix II of the CITES convention, so their international trade is regulated.

Table of contents

• What is oud?
• How does oud form?
• Wild oud and induced oud
• Natural, induced, enhanced and scented oud: what is the difference?
• Where does oud come from?
• Oud grades, prices and adulteration
• Oud oil
• Oud in perfumes
• How is oud burned?
• A brief history of the oud trade
• Oud and CITES
• Tips for buying oud
• Frequently asked questions
• Read also
• References

What is oud?

Oud is an aromatic wood from trees of the genera Aquilaria and Gyrinops [1]. The scent is not in healthy wood, because a healthy tree does not produce these aromatic compounds [2]. Instead, the resin forms in its wood in response to a wound or an infection [3]. The pieces saturated with this resin are the oud that is burned and from which oil is distilled [2].

More than 150 compounds have been identified in oud so far, most of them sesquiterpenoids and chromones [2].

Its Arabic names include “oud” and “aluwwa”. The name “aluwwa” goes back to ancient Indian names for it, such as the Sanskrit agaru [3].

How does oud form?

The aromatic resin forms when the tree is wounded or attacked by insects or fungi, and the tree secretes it as a means of defense [2]. This is rare in the wild: the chance of finding oud in wild Aquilaria trees is low, between 1% and 2% according to one review [4], and about 10% according to another [5]. Its formation in nature is slow and takes many years: up to ten years according to one review [4], and twenty years or more according to another [5].

The scent of oud varies with many factors [3]:

• The species of the tree and where it grows.
• The part of the tree the piece comes from: the trunk, the branches or the roots.
• The time since the infection.
• The method of harvesting and processing.

Wild oud and induced oud

Wild oud forms without intervention, after the tree is infected in the forest [4]. Drilling holes in the tree, driving nails into it or wounding it deliberately, on the other hand, are methods for inducing the resin in cultivated trees [4]. So they should not be described as the way natural oud forms.

Induction by wounding has been known since ancient times. In China, around 300 CE, it was recorded that cutting the tree changes the color of its inner tissues within a year, because the resin forms [3].

Today's induction methods fall into three categories [4] [5]:

• Physical: such as driving nails, drilling holes, burning, breaking the trunk and removing the bark. They are cheap, but they usually produce lower-quality oud, their yield is uncertain, and the resin stays limited to the wounded spots [4].
• Biological: the tree is inoculated with fungi, and the quality of the result is inconsistent [4].
• Chemical: stimulating substances are injected into the tree, and these methods are faster and more consistent. The same review reported that a carefully formulated inducer produced oud close in quality to natural oud [4].

So induced oud is real oud, but its quality varies with the induction method [5]. We found no fixed period between wounding and harvest in the references we consulted.

Natural, induced, enhanced and scented oud: what is the difference?

Type	What it is	What to ask about
Natural oud	Wood in which the resin formed after the tree was wounded or infected in the wild [5]	The source of the piece and its grade
Induced oud	Wood from cultivated trees that were deliberately wounded or treated so the resin forms in them. It is real oud, and its quality varies with the method [5]	The source of the piece and its grade
Enhanced oud	A trade description for which we found no standard definition in a scientific or regulatory reference. It may mean oud with something added to strengthen its scent	What was added to it, and the origin of the wood
Scented oud	Pieces of wood saturated with aromatic oils [6]; the scent depends on the aromatic blend	Its notes

If you see the words “natural” and “enhanced” together in a product name, ask the seller: what does the enhancement mean, and what was added to the wood?

Where does oud come from?

The natural range of the genus Aquilaria extends across South and Southeast Asia [1]:

• Assam, Bangladesh and the eastern Himalayas.
• Southern China and Hainan Island.
• Myanmar, Thailand, Laos, Cambodia and Vietnam.
• The Malay Peninsula, Sumatra and Borneo.
• The Philippines, the Moluccas and New Guinea.

The Arabian Peninsula is not part of its natural range [7]. Oud in the Gulf comes from the producing countries through trade, as it has for centuries [3].

On the market, oud pieces are named after their countries, such as Indian, Cambodian and Indonesian oud [7]. Traders attribute a distinctive scent to the oud of each country [7], but we found no scientific source that describes a fixed scent for the oud of each country. The scent is affected by many factors other than the country, as explained above [3]. Traders in the UAE market rank oud by its country, with Indian and Cambodian oud at the top [7]. This is a market preference, not a scientific standard.

So we suggest treating the country name as the seller's description, and smelling and trying the piece before you judge it.

Oud grades, prices and adulteration

Oud grades vary by resin content, specific gravity and color, and sometimes scent [2]. The price per kilogram ranges from 100 to 100,000 US dollars depending on quality, according to a scientific review published in 2019 [2].

There is no standard system for grading oud. Each country has its own traditional grades, and grading relies on human experience alone [4]. Grades are usually judged by experts by sight and smell, so some personal judgment remains [5].

Oud adulteration has a long history. In the mid-eighteenth century, the Frenchman Pierre Poivre described blackening resin-free wood by coating it with another resin and fumigating it with the smoke of genuine oud [3]. Today, fake or adulterated woods are sold on the market as cheaper oud [2], and pieces may be polished and colored [7]. Demand has raised prices, which has increased adulteration and substitution [3].

Oud oil

Oud oil is an oil extracted from oud wood by distillation [3]. In traditional hydrodistillation, sun-dried pieces with dark resin are soaked in water for two to three months, then boiled to extract their oil [2].

The oil is usually distilled from oud with a lower concentration of oil. Pieces rich in resin, on the other hand, are usually burned directly [3].

Not every product called “oud oil” is an oil distilled from oud wood. It may be an oil-based perfume with an oud character, and the proportion of oud in oil products varies widely [7]. So read the product's description and label, and ask the seller about its ingredients.

Oud in perfumes

Oud oil is an important element of Arabian perfumes, and it has gained a presence in the modern Western fragrance industry [3]. It is often used as a base note, because it has a rich scent, evaporates slowly and its scent lasts a long time [3].

When you see “oud” among a perfume's notes, it describes the character of the scent. The notes alone do not show where this scent comes from, so ask about the ingredients if that matters to you.

How is oud burned?

In the markets of the Middle East and Asia, oud pieces rich in resin are burned directly, without processing or added fragrances. Oud with less resin is often mixed with other aromatic ingredients in bakhoor (incense) blends [3]. The piece is placed on hot charcoal in an incense burner, or in an electric burner that heats it without charcoal.

A Kuwaiti study recommended an electric burner instead of charcoal or an open flame [6]. So we suggest the following:

• An electric burner for use inside the home, with ventilation.
• Light the charcoal in an open place, keep the room well ventilated while the embers are burning, and do not leave it in a closed room or a bedroom. The US CDC advises never burning charcoal indoors and fitting a carbon monoxide detector near sleeping areas [8].
• Start with a small piece, and add more if needed.

Burning and ventilation are explained in detail in our guide Types of Bakhoor.

A brief history of the oud trade

• Oud was described as an aromatic material in Sanskrit texts from about 1400 BCE [3].
• Its trade is more than two thousand years old [2]. This trade carried oud from the producing regions in Southeast Asia to the consuming regions in the Middle East, India, China and Japan [3].
• Arabs and Indians were among the most prominent traders of the Indian Ocean between the seventh and eleventh centuries CE. The sources mention an Ibadi merchant of Omani origin who traveled to China in the mid-eighth century and bought oud there [3].
• In many Middle Eastern societies, oud is used on religious and social occasions, as a sign of status, and to scent the home and personal belongings [3].

Oud and CITES

CITES is the Convention on International Trade in Endangered Species of Wild Fauna and Flora. Oud was listed under it in two stages [1] [9]:

• The species Aquilaria malaccensis alone, in Appendix II since 16 February 1995.
• All species of the genera Aquilaria and Gyrinops, by a decision of the Conference of the Parties in 2004, with the listing in effect since 12 January 2005.

Appendix II does not necessarily mean that a species is threatened with extinction. It means that it may become so unless its trade is strictly regulated [3]. So the international oud trade is regulated.

The reason is that rising demand increased illegal harvesting from forests and the depletion of wild oud [3]. Some Aquilaria species are classified as “Critically Endangered” on the Red List of the International Union for Conservation of Nature (IUCN), such as A. malaccensis, A. crassna and A. rostrata, and some are classified as “Vulnerable”, such as A. sinensis, according to the 2018 assessments [10]. High prices have encouraged planting the trees and inducing oud in them [3].

Tips for buying oud

• Know what you are buying: is it oud pieces, scented oud or “enhanced” oud? Each has a different meaning, as shown in the table above.
• Do not judge by a single sign: density and color are among the grading criteria [2], but pieces may be polished and colored [7]. Grades are judged by sight and smell, and involve some personal judgment [5].
• Do not judge by price alone: prices vary widely by grade [2], and adulteration exists on the market [2].
• Treat the country name as the seller's description: do not assume it means a fixed scent.
• Ask the seller where the oud comes from: also ask how it formed, if the seller knows.
• Smell and try: start with a small amount, and choose by the scent you want and your budget.

Frequently asked questions

What is the difference between oud and bakhoor?

Oud is an aromatic wood from Aquilaria and Gyrinops trees [1]. Bakhoor is a broader term that covers oud, frankincense and prepared blends. The details are in our guide Types of Bakhoor.

Is induced oud real oud?

Yes. It is wood in which the resin formed after the tree was deliberately wounded or treated, but its quality varies with the method [5].

Does a heavy piece or a dark color indicate quality?

Density and color are among the criteria for grading oud, along with resin content and sometimes scent [2]. But pieces may be polished and colored [7], so do not judge by a single sign.

Why do oud prices vary so widely?

Because oud grades vary by resin content, density, color and scent, and the price per kilogram ranges from 100 to 100,000 US dollars depending on quality [2].

How should I store oud and oud oil?

The details are in our guide How to Store Bakhoor, Oud and Oud Oil.

Read also

• Types of Bakhoor: A Guide to Oud, Frankincense, Maamoul and Mabsous
• How to Store Bakhoor, Oud and Oud Oil: A Storage Guide
• How to Choose Bakhoor and Oud for Home and Occasions

References

1. Layola MRR, Sengupta S, Mallick B, Shil T, Shaw R, Banu F, Chakraborty S, Sardar S, et al. Phylogenetic analysis of the Critically Endangered Aquilaria khasiana (Thymelaeaceae) using barcode markers and chloroplast genome, with updated conservation status. Scientific Reports. 2025;15(1):21511. doi:10.1038/s41598-025-08606-x. PMC12214818. Accessed 27 September 2026.
2. Naziz PS, Das R, Sen S. The Scent of Stress: Evidence From the Unique Fragrance of Agarwood. Frontiers in Plant Science. 2019;10:840. PMC6646531. Accessed 27 September 2026.
3. López-Sampson A, Page T. History of Use and Trade of Agarwood. Economic Botany. 2018;72(1):107–129. doi:10.1007/s12231-018-9408-4. Open access: researchonline.jcu.edu.au/58720. Accessed 27 September 2026.
4. Tan CS, Isa NM, Ismail I, Zainal Z. Agarwood Induction: Current Developments and Future Perspectives. Frontiers in Plant Science. 2019;10:122. PMC6374618. Accessed 27 September 2026.
5. Shivanand P, Arbie NF, Krishnamoorthy S, Ahmad N. Agarwood—The Fragrant Molecules of a Wounded Tree. Molecules. 2022;27(11):3386. PMC9181942. Accessed 27 September 2026.
6. Bu-Olayan AH, Thomas BV. Exposition of respiratory ailments from trace metals concentrations in incenses. Scientific Reports. 2021;11(1):10210. PMC8140077. Accessed 27 September 2026.
7. Antonopoulou M, Compton J, Perry LS, Al-Mubarak R. The Trade and Use of Agarwood (Oudh) in the United Arab Emirates. Petaling Jaya, Selangor, Malaysia: TRAFFIC Southeast Asia; 2010. traffic.org. Accessed 27 September 2026.
8. Centers for Disease Control and Prevention (CDC). Carbon Monoxide Poisoning Basics. cdc.gov/carbon-monoxide/about. Accessed 27 September 2026.
9. UNEP-WCMC, CITES Secretariat. Species+: Aquilaria malaccensis. speciesplus.net. Accessed 27 September 2026.
10. Wang HL, Wong TH, Liu KYE, Tsang HLR, Lau DTW. 3D documentation and classification of incense tree Aquilaria sinensis (Lour.) Spreng. wounds by photogrammetry and its potential conservation applications. Ecology and Evolution. 2024;14(6):e11536. doi:10.1002/ece3.11536. PMC11199186. Accessed 27 September 2026.

Prepared and edited by: Sedr Al-Khaleej Perfumes team

Last reviewed: 27 September 2026