Long Dan
Naming
Long Dan (Radix Gentianae)——Shen Nong Ben Cao Jing (Shen Nong’s Herbal)
Origin
The root or rhizome of perennial herb Gentiana scabra Bge or Ctriflora pall or G. manshurica Kitag of family Gentianaceae.
Location
All over in China, mainly from Northeast China.
Harvest
Dig and collect in autumn.
The actual smell and taste
Slight smell, much bitter taste.
Best quality
The best one in yellow or yellowish brown.
Processing
Unprocessed.
Property
Bitter and cold; liver, gallbladder, stomach and bladder meridians entered.
Actions
Clear heat and dry dampness, purge fire and remove toxicity.
Indications
A. Syndrome of damp-heat in liver, gallbladder and lower energizer
It is commonly used for jaundice, leukorrhagia, itching and swollen vagina, stranguria, eczema due to damp-heat, because it has good actions for clearing heat and drying dampness. For being good at clearing damp-heat of liver, gallbladder and bladder, it is mainly used for lower energizer damp-heat syndrome such as jaundice, leukorrhagia, itching and swollen vagina and stranguria. It is used to treat damp-heat jaundice, often combined with heat-clearing, dampness-excreting and anti-icteric herbs. It is used to treat itching and swollen vagina, yellow and stinking leukorrhagia, damp itching and swollen painful scrotum and eczema with pruritis due to damp-heat pouring down, usually combined with heat-clearing and dampness-drying herbs such as Huang Bo and Ku Shen together. Their decoction can be applied to wash externally or do the compression by using the powder. It is used to treat damp-heat stranguria syndrome, often combined with stranguria-relieving herbs such as Zhi Zi and Che Qian Zi, as in Long Dan Xie Gan Tang from Yi Fang Ji Jie (Collection of Prescriptions with Expositions) mainly indicated for all the above syndromes and flank pain due to damp-heat and the swelling of ears with pus discharge.
B. Excess heat of liver and gallbladder and accumulated stomach fire
It can both clear damp-heat and purge excess fire from liver and gallbladder, and is indicated for headache, dizziness, bloodshot eyes, swollen ears due to up-flaming of liver-fire or flank pain and bitter mouth due to excess liver fire. For instance, Long Dan Xie Gan Tang from Yi Fang Ji Jie and Dang Gui Long Hui Wan from Dan Xi Xin Fa are both indicated for the above syndromes. It is used to treat infantile convulsions, often combined with liver-fire-purging herbs and wind-extinguishing and convulsions-stopping herbs for this herb has strong actions of purging liver fire and extinguishing wind and stopping convulsions. For instance, it is often combined with Niu Huang]] and Gou Teng in Liang Jing Wan from Xiao Er Yao Zheng Zhi Jue. It can purge stomach fire, and is also indicated for mouth sores, hematemesis, hemafecia due to accumulated stomach fire. It is often combined with blood-cooling and toxicity-removing herbs. For instance, it is combined with Huang Lian in Long Dan Wan from Zheng Zhi Zhun Sheng.
C. Abscess and swelling due to heat toxin, sore throat
This herb can also be used to clear heat and remove toxicity, as well as to treat abscess due to heat toxin. For infantile sores and swelling, it is mainly combined with heat-clearing and toxicity-removing herbs such as Huang Lian and Sheng Ma in Long Dan Wan from Yi Zong Jin Jian.
For sore throat due to heat-toxin, the single herb can work or is combined with toxicity-removing and sore-throat-relieving herbs. For instance, in Ben Cao Hui Yan (Collection of Speeches on Materia Medica), it is suggested that this single herb should be smashed and its juice should be taken to gargle and swallow.
Dosage and Administrations
Decoct 2～6 g. Proper dosage is for external application.
Cautions
It is contraindicated for deficiency cold syndrome.