Longan (long yan hua or long yan rou)

What is longan? What is it used for?

Longan is a type of tree similar to the lychee. There is some debate as to where the plant originated: some say it first appeared in China, others in India. The tree can reach a height of more than 60 feet, with dense foliage, brittle wood, yellow-brown flowers, and a cork-like bark that is easily peeled and split.

The longan tree bears fruit that is similar in appearance to a lychee nut, except that they are smaller, smoother, and darker in color. The fruit are usually harvested from the tree by hand and sold in bunches. Both longan flowers (long yan hua) and fruit (long yan rou) are used in herbal preparations, but the fruit is used much more frequently. It can be eaten raw or cooked; in some countries, it is also used as a dessert.

Longan contains several vitamins and minerals, including iron, magnesium, phosphorus and potassium, and large amounts of vitamins A and C. In traditional Chinese medicine, longan is considered to have a sweet taste and warm energy, and is associated with the Heart and Spleen meridians. It is used to relieve rapid heartbeat, insomnia, forgetfulness and anxiety associated with blood and qi deficiency. Combined with other herbs such as ganoderma and spirit poria, longan promotes tranquility and calms the spirit. It also increases physical stamina.

How much longan should I take?

The average dose of longan is 9-15 grams, served as a decoction by means of simmering several longan fruits in boiling water. Longan may also be eaten raw or in slices, and the pulp of the fruit can be mashed or added to other beverages.

What forms of longan are available?

Whole, raw or processed longan is available at many Asian markets and Chinese herbal shops. Some stores may sell longan powders.

What can happen if I take too much longan? Are there any interactions I should be aware of? What precautions should I take?

Longan is considered a safe herb. The American Herbal Products Association has given longan fruit a class one rating, meaning it can be consumed safely when used appropriately; however, eating excessive amounts of longan may cause indigestion.

References

• Huang CJ, Wu MC. Differential effects of foods traditionally regarded as "heating" and "Cooling" on prostaglandin e(2) production by a macrophage cell line. J Biomed Sci Nov/Dec 2002;9(6):596-606.
• McGuffin M, Hobbs C, Upton R, et al. (eds.) American Herbal Products Association’s Botanical Safety Handbook. Boca Raton, FL: CRC Press, 1997, p. 42.
• Nong XX, Li M. Pharmacologic effects of an extract of arillus longan (Lour.) Steud. and gecko. Zhongguo Zhong Yao Za Zhi Jun 1989;14(6):365-7, 383. In Chinese.
• Ryu J, Kim JS, Kang SS. Cerebrosides from longan arillus. Arch Pharm Res Feb 2003;26(2):138-42.
• Teeguarden R. Radiant Health: The Ancient Wisdom of the Chinese Tonic Herbs. New York: Warner Books, 1998, p. 191.