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Longdan (Gentianae Radix)

Bitter, cold, very cold, non-toxic. Primarily treats chills and fever alternating between the bones, convulsions and epilepsy, expels pathogenic factors, reconnects severed injuries, stabilizes the five Zang organs, kills gu poison, eliminates latent heat in the stomach, treats seasonal warm febrile diseases, diarrhea and dysentery caused by heat, removes small intestinal parasites, benefits Qi of the liver and gallbladder, stops fright and tremors. Long-term use enhances intelligence and prevents forgetfulness, lightens the body, and delays aging. Also known as Lingyou. Grows in the valleys of Quchu Mountain and Yuanju in Qi region. Roots are harvested in February, August, November, and December, and dried in the shade. (Guanzhong (Cyathulae Radix) serves as its guiding herb; it is incompatible with Fangkui (Adenophorae Radix) and Dihuang (Rehmanniae Radix).)

Tao Hongjing stated: Currently produced along nearby routes, with those from Wuxing being superior. The shape resembles Niuxi (Achyranthis Bidentatae Radix), and the taste is extremely bitter, hence named "Dan" (gallbladder/bitter). According to notes in other editions: The leaves resemble Longkui (Solanum nigrum L.), and the taste is bitter like gall, thus the name. Ministers Yuxi et al., according to *Yaoxing Lun*, state: Longdan is a sovereign drug. It can generate cures for pediatric convulsions and epilepsy, enters the Heart meridian, treats high fever, bone-steaming heat, carbuncles and swellings, treats epidemic diseases, heat jaundice, and mouth ulcers. Rihua Zi stated: Xiaodou (Vigna angularis) serves as its guiding herb. Treats ke-wu (alien qi invasion) and gan accumulation, delirious speech due to febrile diseases, sores and scabies, brightens the eyes, stops irritability, enhances intelligence, and treats forgetfulness.

*Tujing* states: Longdan grows in the valleys of Quchu Mountain and Yuanju in Qi region, and is now also found along nearby routes. The perennial root is yellowish-white, drawing out more than ten roots downwards, resembling Niuxi (Achyranthis Bidentatae Radix).

It grows straight upward into seedlings, over one chi tall. Leaves emerge in April, slender like willow leaves, stems like small bamboo twigs. Flowers bloom in July, resembling Ipomoea flowers, bell-shaped, blue-green. Seeds form after winter, and the seedling withers. Roots are harvested in February, August, November, and December, and dried in the shade. Commonly called Caolongdan (Herbal Gentian). In central Zhejiang, there is Shanlongdancao (Mountain Gentian Herb), which has a bitter and astringent taste. The roots are finely chopped, soaked overnight in fresh ginger juice to remove their harsh nature, baked dry, pounded, decocted in water, and taken orally as one qianbi dose, warm. It treats pain in the four limbs. There is no specific time for harvesting. The leaves do not wither after frost and snow; this is a similar species but distinct variety. Ancient formulas often used it for treating jaundice. *Jiyan Fang* Gu Dan Wan (Grain Jaundice Pill): Kushen (Sophorae Flavescentis Radix) 3 liang, Longdan 1 liang. Sift these two substances together, mix with ox bile to form pills. Take before meals with wheat drink, five pills the size of wutong seeds, three times daily. If ineffective, slightly increase the dose. *Shanfan Fang* treats Lao Dan (Consumption Jaundice), using the same Longdan, increased to 2 liang, plus 37 Zhizi Ren (Gardeniae Semen) kernels. Sift and pound the three substances together, form pills with pig bile, take as previously described, down with drink. The explanation states: Lao Dan is named due to labor/overwork. Gu Dan is named due to food-induced labor/digestion issues.

Lei Gong stated: After harvesting, dry in the shade. When preparing for use, cut off the hairy earthy head with a copper knife, chop, soak overnight in Licorice Decoction (Gancao Tang), strain out the next morning, and sun-dry for use. Do not administer on an empty stomach, as it may cause urinary incontinence. *Shenghui Fang*: Treats roundworm attacking the heart causing stabbing pain and vomiting clear fluid. Longdan 1 liang, remove the head, chop. Add two zhan of water, boil to obtain one zhan, remove dregs. Fast overnight, take in one dose at dawn. *Waitai Miyao*: Treats sudden continuous hematochezia. Longdan one hukou (approx. 1 liang), add five sheng of water, boil to obtain 2.5 sheng, divide into five doses, until cured. *Zhouhou Fang*: Treats sudden heart pain. Longdan 4 liang, wine 3 sheng, boil to obtain 1.5 sheng, take in one dose.