Agarwood (also known globally as Oud, Aloeswood, or Eaglewood) is the resinous heartwood of the Aquilaria tree. During its growth, when certain species of the Aquilaria tree (belonging to the Thymelaeaceae family) are subjected to external impacts or damage, the tree creates a defensive reaction. Over time, a fragrant, oil-like resin accumulates and spreads, transforming the wood molecules. This process creates wood with various colors (brown, gray, indigo, black), physical properties (hard, soft, pliable, brittle), flavor profiles (fragrant, bitter, spicy, sour, sweet), and shapes (round, twisted, flat, long) across different parts of the tree (trunk, branches, roots). This precious material is traded internationally under the commercial name Agarwood (or Oud).
The most outstanding characteristic of Agarwood is the distinct, exquisite fragrance it releases when burned. Depending on the level of resin infection, color, scent, shape, weight, and origin, Agarwood is known by various local names such as Trầm mắt tử (bud-eye agarwood), Trầm bông (floral agarwood), Trầm kiến (ant agarwood), and more.
Based on quality grading, Agarwood is generally classified into three main tiers, each divided into multiple sub-categories:
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First Grade – Ky Nam (Kynam / Kyara): This is the highest quality of Agarwood with the highest resin concentration (the wood molecules are almost entirely infused with oil). When tasted, it presents a complex profile of sour, spicy, bitter, and sweet flavors. It emits a natural fragrance even without heat. When burned, it releases a spectacular aroma with green smoke that rises straight and high into the air. Kynam is divided into 4 types: Bạch kỳ (White), Thanh kỳ (Green/Blue), Huỳnh kỳ (Yellow), and Hắc kỳ (Black). Ancient texts rank them as: First White, Second Green, Third Yellow, and Fourth Black.
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Second Grade – Trầm (Standard Agarwood / Oud): This grade contains less resin than Kynam. It has a bitter taste and mostly releases its fragrance only when burned. The smoke is white, swirling briefly before dissipating. By quality, it is graded from 1 to 6, with further sub-classifications in each tier. Ancient texts categorized it into 5 types, with Hoàng lạp trầm being the most superior.
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Third Grade – Tốc (Early-stage Agarwood / Toc): Toc has a lower level of resin infection, primarily forming from the outside and running along the wood grain. There are many types of Toc (e.g., ant-toc, stone-toc, fragrance-toc), but they generally fall into 4 main groups: Tốc đĩa (plate toc), Tốc dây (wire toc), Tốc hương (fragrance toc), and Tốc pi. Among these, Tốc đĩa is usually highly regarded for its quality.
To date, there is no official governmental or organizational document standardizing the grading of Agarwood. According to Dr. Le Cong Kiet, evaluation criteria typically rely on: origin, scent intensity, fragrance profile, shape, size, color, weight, density, purity, and the specific Aquilaria species. In the commercial Oud market, classification is largely based on human experience, sensory evaluation (looking, touching, carving, burning, tasting, smelling), and mutual agreement between buyers and sellers.
The Ultimate Benefits and Uses of Agarwood
Agarwood is an incredibly rare and precious medicinal material.
1. In Traditional Eastern Medicine
Agarwood is highly revered as a rare botanical remedy. It is spicy, warm in nature, and works to regulate "qi", warm the kidneys, and balance the liver. It is traditionally used to treat abdominal pain, chest pain, vomiting, asthma, urinary retention, fever, and breathing difficulties, while acting as a painkiller, sedative, and aphrodisiac.
Historically, renowned Vietnamese traditional medicine practitioners like Hai Thuong Lan Ong (18th century) and Tue Tinh (14th century) documented its uses. Tue Tinh wrote: "Spicy flavor, highly fragrant, warm nature; it clears the senses, treats toxins, expels evil winds, warms the stomach, tonifies the primal yang, and aids digestion." Hundreds of traditional remedies utilize Agarwood for its potent healing properties.
2. In Modern Western Medicine
Modern science has shown that Agarwood possesses strong antibacterial properties and promotes rapid wound healing. It is effective in supporting treatments for cardiovascular issues (heart failure, chest pain), respiratory diseases (asthma), neurological conditions (insomnia, pain relief, tranquilization), digestive problems, and urinary issues.
Notably, Japanese researchers have discovered a new Sesquiterpene in Vietnamese Kynam (from Khanh Hoa province). Laboratory tests proved its stimulating effect on the growth of BDNF (Brain-Derived Neurotrophic Factor), a vital protein for brain and nerve cell health. This groundbreaking research may explain why Japan currently holds the world's largest reserve of Kynam.
3. The Power of Agarwood Essential Oil (Oud Oil)
Extracted from resinous Agarwood or Aquilaria wood, Oud oil is a viscous, yellow or amber liquid with an unmistakable, deeply complex aroma. The quality, scent profile, longevity, and price of the Oud oil depend heavily on the Aquilaria species it is extracted from.
Oud oil is widely used in pharmaceuticals, premium cosmetics, and high-end perfumery. It holds profound spiritual and cultural significance, especially among Muslims in the Middle East. In cosmetics, Oud-infused creams and perfumes are believed to help rejuvenate the skin, clear blemishes, and adjust pores naturally. It is celebrated as the "eternal friend of beauty," providing a refreshing and uplifting effect on the wearer.
4. Spiritual and Aromatic Appeal
Agarwood is highly flammable and releases a mesmerizing, unmatched fragrance when burned. In Eastern cultures, burning Agarwood incense is a deeply ingrained tradition for honoring ancestors, deities, and heaven and earth. It is burned to purify spaces, ward off negative energy, and attract good fortune.
Across various religions (Buddhism, Islam, Hinduism), the scent of Oud is considered a bridge between the physical and spiritual worlds. From ancient palaces to modern temples and lavish mansions, burning Agarwood remains the most noble form of spiritual offering. Enjoying the scent of Oud is considered an elegant hobby that promotes well-being and reflects high socioeconomic status, particularly in Japan and Taiwan.
Furthermore, premium Agarwood is sought after as a high-value collectible, an elite diplomatic gift, and a luxurious decorative item for royalty and high-ranking officials to bring good fortune and ward off toxic winds.
Which Tree Species Produce Agarwood?
Agarwood comes from the Aquilaria tree, but not every species produces it. Botanically, there are about 25 Aquilaria species worldwide, but only 19 are known to produce Agarwood:
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Aquilaria grandiflora Bth (China)
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A. sinensis Merr / A. chinesis (China)
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A. yunnanensis S.C.Huang (China)
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A. beccariana Van Tiegh (Malaysia, Indonesia)
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A. microcarpa Baill (Malaysia, Indonesia)
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A. hirta Ridl (Malaysia, Indonesia, Singapore)
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A. rostrata Ridl (Malaysia)
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A. subintegra Ding Hou (Thailand)
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A. malaccensis Lam (India, Bhutan, Malaysia, Indonesia, Laos, Thailand)
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A. moszkowskii Gill (Indonesia)
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A. cumingiana (Decne) Ridl (Philippines)
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A. filaria (Oken) Merr. (Philippines)
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A. apiculata Merr. (Philippines)
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A. acuminate (Merr.) Quis (Philippines)
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A. crassna Pierrei ex Lecomte (Vietnam, Cambodia, Laos)
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A. baillonii Pierrei ex Lecomte (Vietnam, Cambodia)
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A. banaense P.H.Ho (Vietnam)
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A. rugosa L.C.Kiet & P.J.A.Kessler (Vietnam)
19. A. khasiana H.Hallier (India, Bhutan)
The Superiority of Vietnamese Agarwood
In Vietnam, there are 4 main Aquilaria species officially identified to produce Agarwood. The most prominent is Aquilaria crassna (commonly known in Vietnam as Cây Dó Bầu), found nationwide from Hoa Binh to Kien Giang. According to forestry experts, Vietnam also possesses two additional resin-producing species: G. vidalii (Dó bụi) and Linostma deccandrum (Dó leo).
According to Professor Gishi Honda (University of Tokyo, Japan), Vietnamese Agarwood is the highest quality in the world. This historical truth was recorded by the scholar Le Quy Don (1726 - 1784): "Kynam originating from Binh Khang and Dien Khanh in Quang Nam is the absolute best; those from Phu Yen and Quy Nhon rank second."
During the Nguyen Lord era, Southeast Asian Buddhist and Islamic nations heavily favored the Agarwood from Vietnam's Quang region. Today, organizations and individuals across Vietnam are actively cultivating Aquilaria crassna to meet the soaring global demand for premium Agarwood and Oud oil.
Source: Vietnam Agarwood Association