The ancient Chinese people had long used longan for health preservation and treating illnesses, considering it a nourishing medicinal herb with effects such as replenishing qi and blood, and calming the spirit. It can treat conditions like insomnia, forgetfulness, palpitations, physical weakness and emaciation, and edema in postpartum women.
“Its exterior is gilded gold, its core holds white jade skin; when split, they scatter on plates, each a luminous pearl of the night.”
— Song Yu, a literary scholar, calligrapher, and seal carver of the Ming Dynasty
Longan is a subtropical, perennial, evergreen tree that originated in China. It mainly grows in regions such as Fujian, Taiwan, Hainan, Guangdong, Guangxi, Yunnan, southern Guizhou, and Sichuan. Depending on the variety and growing region, longan trees can typically live for over a hundred years, with the fruit maturing annually from July to October and the fruit-bearing age lasting for seventy to eighty years. The ancient Chinese people consumed longan very early on and also cultivated it. The "Shennong Ben Cao Jing" of the Eastern Han Dynasty states: "Longan is named Yizhi, and grows in the mountain valleys of the Nanhai." The "Book of the Later Han" records: "The seven commanderies of Jiaozhi presented longan, showing that longan has been valued since the Han Dynasty." The Nanhai and Jiaozhi mentioned in the Han Dynasty correspond to the Lingnan region of present-day Guangdong.
Longan has many aliases, such as Longmu, Lizhu, Yizhi, Yuanyan, Guiyuan, Mipi, Lizhi Nu, and Chuan Danzi. Some documents explain the origin of certain aliases. The "Bencao Gangmu" of the Ming Dynasty says: "Longan, Longmu, are named for their shape." The "Lingbiao Luyi" of the Tang Dynasty explains "Lizhi Nu" as "When the lychee season is over, the longan ripens immediately, so people in the south call it the 'slave of lychee.'"
The ancient Chinese people had long used longan for health preservation and treating illnesses, considering it a nourishing medicinal herb with effects such as replenishing qi and blood, and calming the spirit. It can treat conditions like insomnia, forgetfulness, palpitations, physical weakness and emaciation, and edema in postpartum women. Longan flesh can be eaten alone or made into longan paste, such as the "Yuling Gao" recorded by the Qing Dynasty physician Wang Shixiong in his "Suixi Ju Yinshipu." This is a prepared medicine made by steaming longan flesh with rock sugar (the amount used is about one-tenth of the longan flesh). It is claimed to have the effect of "greatly replenishing qi and blood, its strength surpassing that of ginseng and astragalus," and can be taken with hot water to treat those with qi and blood deficiency. It is also considered very suitable for women to take before childbirth. Longan can also be combined with other herbs to form various prescriptions for therapeutic purposes. One example is the "Guipi Tang" recorded by the Song Dynasty physician Yan Yonghe in his "Jisheng Fang," which has effects such as strengthening the spleen and nourishing the heart, and replenishing qi and blood. It remains a famous prescription commonly used for health and medical purposes today.
In addition, longan flesh can be made into various foods with other ingredients. "Babao Fan" (Eight-Treasure Rice) and "Babao Zhou" (Eight-Treasure Porridge) are well-known desserts, while soups like longan with lotus seeds, longan with red dates, and longan with red beans can also be used for dietary therapy.
Modern scientific experiments have found that longan flesh is rich in glucose, riboflavin, potassium, magnesium, and phosphorus, with a particularly high content of selenium. It also contains relatively large amounts of sucrose, tartaric acid, niacin, choline, protein, and dietary fiber. It has been reported that longan flesh may also contain substances that delay aging. Therefore, consuming a moderate amount of longan flesh in daily life is beneficial to the body. However, Traditional Chinese Medicine believes that people with indigestion, a thick greasy tongue coating, a sore red throat, toothache, or internal heat due to yin deficiency should temporarily avoid eating longan.
In addition to using longan flesh for health and medical purposes, Chinese medical literature also records the therapeutic effects of the longan seed, shell, and leaves. The longan seed is calcined until charred, then ground into a fine powder (named "Lizhu San"), which can be applied topically to the site of a trauma to stop bleeding, relieve pain, and reduce post-healing scars. The "Bencao Gangmu" records that grinding six longan seeds and 14 Sichuan pepper grains into a fine powder can be used to treat underarm bromhidrosis. The longan shell is calcined until charred, ground into a fine powder, and mixed with tea oil to form a paste, which can be used topically to treat burns and chronic skin ulcers that do not heal. Furthermore, a decoction of longan leaves can be used for external washing to treat sores and swellings.
The wood of the longan tree has a fine, dense grain, is hard and durable, and has a pleasing purple color, making it a superior material for carving handicrafts.