Library

(Registered as a Superior Grade herb in the *Shennong Bencao Jing* [Classic of Materia Medica])

**[Names]** Lingyou (from the *Shennong Bencao Jing*). Li Dang stated: The leaves resemble those of *Solanum nigrum* (Longkui), and the taste is bitter like gall, hence the name.

**[Collection and Explanation]** The *Bielu* [Recorded by Famous Physicians] states: Longdan grows in the valleys of Qiju and Yuanju. The roots should be collected in February, August, November, and December, and dried in the shade.

Tao Hongjing stated: It is now produced in areas near main roads, with those from Wuxing being of superior quality. The root resembles that of *Achyranthes bidentata* (Niuxi) and has a very bitter taste.

Su Song stated: The perennial root is yellowish-white, with more than ten roots sprouting downwards, resembling *Achyranthes bidentata* but shorter. The stem grows straight upwards, over one chi high. In April, tender leaves appear, with thin stems resembling small bamboo twigs. Flowers bloom in July, resembling *Ipomoea nil* (Qian niuhua), bell-shaped, greenish-blue. Seeds form after winter, and the stem withers. Commonly called Caolongdan. There is also Shanlongdan, which tastes bitter and astringent; its leaves do not wither after frost and snow. Mountain people use it to treat pain in the four limbs; it is of the same category but a different species. Collection time is unrestricted.

Root

**[Processing]** Lei Xiao stated: Dry in the shade after collection. When used, cut off the fibrous roots and soil with a copper knife, remove the head, chop finely, soak in Gancao Tang (Licorice Decoction) overnight, drain, sun-dry, and use.

**[Flavor and Properties]** Bitter, astringent, extremely cold, non-toxic.

Lei Xiao stated: Taking it on an empty stomach causes urinary incontinence.

Xu Zhicai stated: Guanzhong (*Cyathula officinalis*) and Xiaodou (Adzuki bean) act as guiding herbs; it is incompatible with Dihuang (*Rehmannia glutinosa*) and Fangkui (*Adenophora stricta*).

**[Indications]** Cold and heat alternating in the bones, fright epilepsy and pathogenic qi, healing fractures and injuries, stabilizing the five Zang organs, killing gu poison (from the *Shennong Bencao Jing*). Eliminating latent heat in the stomach, seasonal warm fevers, heat-type diarrhea and dysentery, removing small intestinal parasites, benefiting Liver and Gallbladder Qi, stopping fright and tremors, long-term use enhances memory and prevents forgetfulness, lightens the body, and promotes longevity (from the *Bielu*). Treating severe fever and bone-steaming heat in children, fright epilepsy affecting the Heart, epidemic diseases causing heat jaundice, carbuncles, sores, and mouth ulcers (Zhen Quan). Guest shock and childhood malnutrition due to heat, manic speech during febrile diseases, brightening the eyes, relieving irritability, treating scabies and tinea (Daming). Removing yellow membranes from the eyes, redness and swelling, protruding pterygium, unbearable pain (Zhang Yuansu). Clearing pathogenic heat from the Liver channel, eliminating damp-heat swelling in the Lower Jiao, draining Bladder fire (Li Gao). Treating sore throat, wind-heat night sweats (Li Shizhen).

**[Elucidation]** Zhang Yuansu stated: Longdan is bitter and cold, with strong flavor and properties, sinking and descending, belonging to Yin. It is a herb for the Qi level of the Foot Jueyin Liver and Foot Shaoyang Gallbladder channels. Its functions are fourfold: first, clearing damp-wind in the lower part of the body; second, clearing damp-heat; third, treating swelling and pain from the umbilicus down to the feet; fourth, treating cold-damp jiaogix (foot disease). Its downward action is similar to that of Fangji (*Stephania tetrandra*); when soaked in wine, it can ascend. Externally, using Chaihu (*Bupleurum*) as the chief herb and Longdan as the assistant is essential for treating eye diseases. Wang Haogu stated: It benefits Liver and Gallbladder Qi while draining fire. Li Shizhen stated: Ministerial Fire resides in the Liver and Gallbladder; there is draining but no tonifying. Thus, Longdan's benefit to Liver and Gallbladder Qi lies precisely in its ability to drain pathogenic heat from them. However, being extremely bitter and cold, excessive use may damage the generating Qi of the Stomach, potentially exacerbating fire pathogens. This aligns with the principle that long-term use of Huanglian (*Coptidis Rhizoma*) may transform into fire. The claim in the *Bielu* that long-term use lightens the body is likely untrustworthy.

**[Attached Prescriptions]** Four old prescriptions, six new prescriptions.

Typhoid fever with mania: Powder Caolongdan, mix with egg white and white honey, dissolve in cool water, and take 2 qian (from *Shanghan Yunyao*).

Pain in the four limbs: Fine-cut Shanlongdan root, soak overnight in fresh ginger juice to mitigate its harsh nature, bake dry, powder, decoct in water, take 1 qian bi, warm administration.

Gu Dan (Grain Jaundice) and Lao Dan (Labor Jaundice): Gu Dan arises from dietary indiscretion; Lao Dan arises from overexertion. Use 1 liang of Longdan and 3 liang of Kushen (*Sophorae Flavescentis Radix*). Powder them, pillify with ox bile into pills the size of wutzu seeds. Take 5 pills before meals with wheat drink, three times daily; increase dosage slightly if ineffective. For Lao Dan, add 1 liang of Longdan and 37 seeds of Zhizi (*Gardeniae Fructus*), pillify with pig bile (from *Shanfan Fang*).

All types of night sweats: For women and children with all types of night sweats, and for persistent night sweats after typhoid fever. Powder Longdancao, take 1 qian per dose, mix with 3 liang of pig bile, add a little warm wine, and take (from *Yangshi Jiancang Fang*). For children with night sweats and fever: Equal parts Longdancao and Fangfeng (*Saposhnikoviae Radix*). Powder them. Take 1 qian per dose, mixed with rice drink. Can also be taken as pills or decocted.

Hot and painful sore throat: Grind Longdan with water and ingest (from *Jijian Fang*).

Dry eyes during summer travel: 1 he of fresh Longdan (pressed juice), 1 spoon of Huanglian (*Coptidis Rhizoma*, two cun long, crushed and steeped for juice), mix and apply to eyes (Wei Shi's *Defang Fang*).

Ocular discharge/pus: Equal parts Longdancao and Danggui (*Angelicae Sinensis Radix*). Powder them. Take 2 qian per dose, washed down with warm water (from *Hongfei Ji*). Pinworms attacking the heart causing stabbing pain, vomiting clear fluid: 1 liang of Longdan, remove head, chop, add two zhan of water, boil to one zhan. Fast overnight, take all at once at dawn (from *Shenghui Fang*). Sudden continuous rectal bleeding: A handful (tiger's mouth measure) of Longdan, five sheng of water, boil to obtain 2.5 sheng, divide into five doses (Yao Sengtan's *Jiyan Fang*).