根皮味辛而有苦。气寒。阴中微阳。入手厥阴足少阴足厥阴经。治血中结气。行血
中伏火凉血。（辛以散结聚。苦寒除血热。故入血分而凉血。）除烦热。和血生血。安五脏。
治神志不足。中风螈 。惊痫邪气。风噤癫疾。通关腠血脉。除风痹。主寒热。（寒热者阴
虚血热之候也）疗无汗之骨蒸。衄血吐血。消扑损瘀血。去肠胃留血。女子经脉不通。血沥
腰痛。治胞下胎。及天行痘疮血热。（诸本草）丹皮入手厥阴足少阴。故治无汗之骨蒸。地
骨皮入足少阴手少阳。故治有汗之骨蒸。（洁古）盖地骨皮为气分之剂。其所治者由阴中阴
之热。以郁阴中之阳气而薰蒸于表者也。所入足少阴手少阳是也。丹皮为血分之剂。其所治
者由阳中阴之热。以沉于阴中阴之血而煎熬于里者也。所入手厥阴足少阴是也。然须与青蒿
子天麦门冬沙参地黄五味枸杞牛膝之属同用。始得其力。能泻阴胞中之火。故四物汤加之。
治妇人骨蒸。（洁古）神不足者。手少阴。志不足者。足少阴。故肾气丸用之以治神志不足。
（又）心虚肠胃积热。心火炽甚。心气不足者。以丹皮为君。（东垣）能行结气。（气之结于
血中者。其伏火。即结气所化也。）而固真气。去瘀血而养真血。（结气行而瘀血化。能化则
能生。故得谓之固真气。养真血。）为滋阴养血必用之药。（嵩）血之所患者火也。能泻阴胞
之火。故吐衄必用。能引血归肝。故呕吐血必用之。入清胃散。治阳明胃经血热齿痛。
〔论〕丹皮入手厥阴足少阴。故能泻阴胞中之火。夫阴胞乃关元血海。上与心胞络紧相
应者也。经曰。胞络者系于肾。又曰。胞脉属心。而络于胞中。先哲释曰。胞即子宫相火之
所在也。心主血脉。君火之所居也。阳气上下交通。故胞脉属心。而络系于肾之胞中。是则
兹物能泻阴胞中之火者。非由手厥阴足少阴所专主乎。顾又云血中伏火者何也。盖六淫七情。
或阴
所化。总而名之曰阴胞中之火也。兹物丹色。合于主血之心。其气寒。合于离中之坎。其味
辛而有苦。合于金火之合德。离含坎火。得金则归心包络而生血矣。辛散苦泄。更并于气之
寒。则降令行而阴引阳以下。胞之脉通矣。（其所散所泄者。乃血中之戾气。故即为之除瘀
和血也。）火得水而胞脉通于心。水得火而胞络固于肾。是为阴胞火泄而神志俱补也。盖火
之精为神。每苦于离中之坎不足。水之精为志。每苦于坎中之离不足。如上下相召以相益。
则此品庶几有之矣。至其能疗肠胃积热者。以心包络与胃口紧相应。固由心而及之耳。抑后
学更取重于足厥阴肝。其理然欤。曰。此味入手厥阴足少阴而和其血之原。夫一阴肝固为独
使。而行其生化之机者。使上之心包络。阴并于阳则肝无以奉其下降之阴。气亦由阴伤化火
矣。如下之血海。阳乘乎阴则肝无以达其上升之阳。气亦因阳郁化火矣。谓足厥阴不与之同
病也可乎。但求其所入。则由心入肾。不先责之为使者耳。夫本经所治寒热。中风螈 惊痫。
固血之
正未可忘乎其源也。（直入阴中而散伏火。伏火散则血自行。非如他药之兼辛温而逐瘀以行
者。其最能引血归肝。职是之故。）冲任督皆起于胞宫。胞即所谓胞门子户。乃男子藏精女
子蓄血之处也。即胞脉属心而络于胞中。可以知气化血。血化精之义矣。肺阴下降入心。然
后气能化血。心气下降入肾。然后血能化精。盖气化血者。金为火用也。血化精者。火为水
用也。皆还其所自始也。火为水用。又何以赤化白。盖水中有金。金气不至于水中。是肺气
不归命门。则亦不能化也。夫火中得金而液化血。水中得金而血化精。故元门炼取水中金。
又曰。气盛则精盈者此也。
缪氏云。功归凉血。如血病于寒涩者。似难概用。能行血。凡血崩及经行过期不净。忌
与行
〔修治〕择根如笔管大者。以铜刀劈破。去骨切片。阴干。酒拌蒸三时。日干用。
The root bark of *Moutan Cortex* (Danpi, 牡丹皮) tastes pungent and bitter, has a cold nature, and belongs to the category of Yin with slight Yang. It enters the Pericardium Meridian of Hand-Jueyin, Kidney Meridian of Foot-Shaoyin, and Liver Meridian of Foot-Jueyin. It treats Qi stagnation in blood, promotes circulation of latent Fire in blood, and cools blood. (Pungency disperses nodules and accumulations; Bitter-Cold eliminates Blood-Heat, thus entering the Blood aspect to cool blood.) It removes vexation and heat, harmonizes and generates Blood, calms the Five Viscera, treats deficiency of Shen (Spirit) and Zhi (Will), convulsions due to Wind-Stroke, pathogenic factors causing惊痫 (Jingxian, epilepsy/fright), wind-induced trismus and epilepsy, unblocks joints, interstices, and vessels, removes Wind-Bi, and primarily treats alternating chills and fever. (Alternating chills and fever are signs of Yin deficiency with Blood-Heat.) It treats bone-steaming without sweat, epistaxis, hematemesis, resolves contusion-related blood stasis, removes retained blood in the intestines and stomach, treats amenorrhea in women, blood dribbling with lower back pain, treats conditions below the Bao (Uterus/Womb), and treats blood-heat in epidemic pox. (From various Materia Medica texts).
Danpi enters the Hand-Jueyin and Foot-Shaoyin meridians, thus treating bone-steaming without sweat; Digupi (Lycii Cortex, 地骨皮) enters the Foot-Shaoyin and Hand-Shaoyang meridians, thus treating bone-steaming with sweat. (Cited from Jiegu). Generally, Digupi is an agent for the Qi aspect; it treats heat arising from "Yin within Yin," where Yang within Yin is constrained and steams outward. Its meridian affiliations are Foot-Shaoyin and Hand-Shaoyang. Danpi is an agent for the Blood aspect; it treats heat arising from "Yang within Yin," which sinks into the Yin-blood and scorches internally. Its meridian affiliations are Hand-Jueyin and Foot-Shaoyin. However, it must be used together with Qinghaozi (Artemisiae Annuae Herba, 青蒿子), Tiandong (Asparagi Radix, 天冬), Maidong (Ophiopogonis Radix, 麦冬), Shashen (Glehniae Radix, 沙参), Dihuang (Rehmanniae Radix, 地黄), Wuweizi (Schisandrae Fructus, 五味子), Gouqi (Lycii Fructus, 枸杞), and Niuxi (Achyranthis Bidentatae Radix, 牛膝) to exert its power. It can drain Fire from the Yin Bao (Uterus/Essence Chamber), so it is added to Siwu Tang (Four Substances Decoction, 四物汤) to treat bone-steaming in women. (Cited from Jiegu). Deficiency of Shen belongs to Hand-Shaoyin Heart; deficiency of Zhi belongs to Foot-Shaoyin Kidney. Therefore, Shenqi Wan (Kidney Qi Pill, 肾气丸) uses Danpi to treat deficiency of Shen and Zhi. (Also stated): For Heart deficiency with accumulated Heat in the intestines and stomach, blazing Heart-Fire, and insufficient Heart-Qi, Danpi serves as the Sovereign herb. (Cited from Dongyuan). It can move stagnant Qi. (Qi stagnating in Blood manifests as latent Fire, which is transformed from stagnant Qi.) It consolidates True Qi, removes blood stasis, and nourishes True Blood. (When stagnant Qi moves, blood stasis transforms; transformation leads to generation, hence it is called consolidating True Qi and nourishing True Blood.) It is an essential herb for nourishing Yin and Blood. (Cited from Song). The disease of Blood is caused by Fire. Since it drains Fire from the Yin Bao, it is essential for hematemesis and epistaxis. Since it guides Blood back to the Liver, it is essential for vomiting blood. In Qingwei San (Stomach-Clearing Powder, 清胃散), it treats toothache due to Blood-Heat in the Yangming Stomach Meridian.
[Discussion] Danpi enters the Hand-Jueyin and Foot-Shaoyin meridians, thus draining Fire from the Yin Bao. The Yin Bao is the Xuehai (Sea of Blood) at Guanyuan, closely corresponding to the Pericardium Collateral above. The Classics state: The Bao collateral connects to the Kidney. Also: The Bao vessel belongs to the Heart and connects to the Bao center. Ancient sages explained: Bao refers to the uterus, where Ministerial Fire resides. The Heart governs Blood vessels and is the residence of Sovereign Fire. Yang and Qi communicate up and down, so the Bao vessel belongs to the Heart and connects to the Bao center of the Kidney. Thus, this substance's ability to drain Fire from the Yin Bao is indeed exclusively governed by the Hand-Jueyin and Foot-Shaoyin meridians. But what is meant by "latent Fire in Blood"? Roughly, Six Excesses and Seven Emotions, or transformations of Yin, are collectively named Fire in the Yin Bao. This herb has a cinnabar-red color, corresponding to the Heart that governs Blood; its cold nature corresponds to Kan Water within Li Fire; its pungent and bitter taste corresponds to the harmony of Metal and Fire. Li contains Kan Fire; receiving Metal energy returns it to the Pericardium Collateral to generate Blood. Pungency disperses, Bitter drains, combined with cold nature, the descending function proceeds, Yin guides Yang downward, and the Bao vessels become unobstructed. (What is dispersed and drained are aberrant Qi in the Blood, thus removing stasis and harmonizing blood.) Fire regulated by water allows Bao vessels to connect to the Heart; Water warmed by Fire secures Bao collaterals to the Kidney. This is how draining Fire from the Yin Bao supplements both Shen and Zhi. The essence of Fire is Shen, often suffering from insufficient Kan (Water) in Li; the essence of Water is Zhi, often suffering from insufficient Li (Fire) in Kan. If they call upon each other mutually to benefit, this herb achieves that. Regarding its treatment of intestinal and gastric accumulated heat, it is because the Pericardium Collateral closely corresponds to the stomach opening, indeed spreading from the Heart. Or do later scholars value it more for its action on the Foot-Jueyin Liver? The answer is: This flavor enters Hand-Jueyin and Foot-Shaoyin to harmonize the source of Blood. Although Foot-Jueyin Liver is indeed the sole envoy, moving the mechanism of generation and transformation, if the upper Pericardium Collateral has Yin merging into Yang, the Liver cannot offer its descending Yin, and Qi transforms into Fire due to Yin injury; if the lower Sea of Blood has Yang overpowering Yin, the Liver cannot reach its ascending Yang, and Qi transforms into Fire due to Yang constraint. Can we say Foot-Jueyin does not share this pathology? But regarding its entry, it goes from Heart to Kidney, not first acting as an envoy. The Chills and Fever, Wind-Stroke convulsions, and Jingxian treated in the Classic are indeed primary Blood diseases, one must not forget their source. (It directly enters Yin to scatter latent Fire; once latent Fire scatters, Blood moves freely, unlike other herbs that use Pungent-Warm properties to drive out stasis; its greatest ability is guiding Blood back to the Liver, for this reason.) Chong, Ren, and Du meridians all originate from the Bao Gong (Uterus), also known as Baomen Zihu, the place where men store Essence and women accumulate Blood. Since Bao vessels belong to the Heart and connect to the Bao center, one can understand the meaning of Qi transforming into Blood and Blood transforming into Essence. Lung Yin descends into the Heart, then Qi can transform into Blood; Heart Qi descends into the Kidney, then Blood can transform into Essence. Qi transforming into Blood is Metal serving Fire; Blood transforming into Essence is Fire serving Water, both returning to their origin. Fire serving Water, how does Red transform into White? Inside Water there is Metal. If Metal energy does not enter Water, Lung Qi does not return to Mingmen, and transformation cannot occur. When Fire receives Metal, Liquid transforms into Blood; when Water receives Metal, Blood transforms into Essence. Hence, the Mysterious Gate refines Metal from Water. It is also said: Abundant Qi leads to abundant Essence.
Mu Xi Yong stated: Its efficacy lies in cooling Blood. For blood diseases caused by Cold and stagnation, it seems inappropriate to use generally. It moves Blood; therefore, it is contraindicated in uterine bleeding and menstrual periods that are overdue and not clearing.
[Processing] Select roots as thick as a pen tube. Split them with a copper knife, remove the woody core, slice, and dry in the shade. Mix with wine, steam for three shichen (6 hours), then sun-dry for use.