养阴凉血。
苦甘而寒，沉阴而降。入手足少阴（心、肾。）厥阴。（心包、肝。）及手太阳经。（小肠）
养
阴退阳。凉血生血。治血虚发热。常觉饥馁。五心烦热。（经曰∶阴虚生内热。）痿痹惊悸。
（有触而心动曰惊、无惊而自动曰悸、即怔忡也、有因心虚火动者、有因肝虚胆怯者、有因
水停心下者、火畏水、故悸也、地黄能交心肾而益肝胆、亦能行水、故治之也。）倦怠嗜卧。
（
胸膈痞闷。（肝胆燥火、闭伏胃中、亦须同归身用。）吐衄尿血
。（痛为血淋、不痛为尿血。）血晕崩中。（经曰∶阴虚阳搏、谓之崩。）调经安胎。利大小便
。性寒而润。脾虚泄泻。胃虚食少。均在禁例。以怀庆肥大而短。糯体细皮、菊花心者佳。
用沉水者。浮者不用。恶贝母。畏芜荑。忌莱菔、葱、蒜、铜铁器。得门冬、丹皮、当归良
。
平补肝肾、养血滋阴。
甘而微温。入足三阴经。滋肾水。封填骨髓。利血脉。补益真阴。聪耳明目。（耳为肾
窍、
目为肝窍、目得血而能视、耳得血而能听。）黑发乌须。又能补脾阴。止久泻。（经云∶肾司
二便、久泻多属肾虚、且下多亡阴、自宜补肾、不可专责脾也。）治劳伤风痹。阴亏发热。
干咳痰嗽。（咳嗽阴亏者、地黄丸为要药、亦能除痰、丹溪曰∶久病阴火上升、津液生痰不
生血、宜补血以制相火、其痰自除、喻嘉言曰∶凡咳嗽渐至气高汗渍、不补其下、但清其上
、必至气脱卒亡、医之罪也。）气短喘促。（熟地一两、归身三钱、炙甘草一钱、名贞元饮、
治气短似喘、呼吸急促、提不能升、咽不能降、气道噎塞、势极垂危者、常人但知气急、其
病在上、而不知元海无根、肝肾亏损、此子午不交、气脱证也、尤惟妇人血海常亏者、最多
此证、宜以此饮济之缓之、傥庸众不知、妄云痰逆气滞、用牛黄苏合、及青陈枳壳破气等剂
、则速其危。）胃中空虚觉馁。痘证血虚无脓。病后胫股酸痛。产后脐腹急疼。（丹溪
曰∶产前当清热养血为主、产后宜大补气血、虽有杂证、从末治之。）感证阴亏。无汗便闭
。（阴气外溢则得汗、阴血下润则便通。）诸种动血。一切肝肾阴亏。虚损百病。为壮水之主
药。
气郁之人。能窒碍胸膈。用宜斟酌。（郭佩兰本草汇曰∶丹溪云∶气病
无害也、不知血药属阴、其
性
凝滞、胃虚气弱之人、过服归地等剂、必
致痞闷食减、病安能愈耶、景岳全书曰∶地黄产于中州沃土之乡、得土气之最浓者也、其色
黄、土之色也、其味甘、土之味也、而谓非脾胃中州之药、吾不信也、但脾胃喜温而恶寒、
生干地黄性寒、自非脾胃所喜、蒸晒极熟、则甘温正与脾胃相宜耳、殊不知熟地黄乃阴滞不
行之药、大为脾胃之病所不宜也。）作熟地黄法。拣取肥地黄沉水者数十斤。洗去沙土。略
晒干。别以拣下瘦小者数十斤。捣绞取汁。投石器中。浸漉令浃。入柳木甑。放瓦锅上蒸一
日。晒几日。令极干。又蒸又晒。如是九次。锅内傥有淋下地黄余汁。亦必拌晒。使汁尽而
干。其地黄光黑如漆。味甘如饴。须瓷器收之。以其脂柔喜润也。（按地黄取其纯阴静重、
近时多拌以好酒及砂仁末而蒸晒之、是反以散动香燥、乱其性矣、其法甚为不善、有用姜汁
拌炒者、尤不合法。今市中惟以一煮而售、害有不可胜言者、盖禀北方纯阴至寒之性、非
太阳与烈火频频交炼则不温、所以固本膏、虽经日煎熬、必生熟各半而用之、设以生地一煮
、便作熟地投用归肾、右归、七味、八味等剂中、则寒凉之性未除、心肾之经各别、以心经
寒凉之药为君主、以肾经温暖之药为臣佐、岂徒无益、反引寒性下损真阳、微虚者、暂堪抵
受、大虚挟寒者、气立孤危、制治乖方、而为害甚烈、斯其最也。市医尝将熟地枸杞等炒
作炭用、是甘润养阴之品、变而为苦燥伤阴之物、非徒无益、而又害之矣。）
Nourishes Yin, clears heat, cools blood, and stops bleeding.
Bitter, sweet, and cold in nature; heavy and descending. Enters the Foot-Shaoyin Kidney Meridian, Hand-Shaoyin Heart Meridian, Foot-Jueyin Liver Meridian, Hand-Juexin Pericardium Meridian, and Hand-Taiyang Small Intestine Meridian.
Nourishes Yin and restrains Yang. Cools blood and generates blood. Treats fever caused by Blood deficiency, where the patient often feels hungry but weak (The *Neijing* states: "Yin deficiency generates internal heat"). Treats flaccidity syndromes (*Wei*), bi syndromes, palpitations and fright (Palpitation triggered by external stimuli is called "Jing" (Fright); spontaneous palpitation without stimuli is called "Ji" (Palpitation), also known as *Zhengchong*. Some are caused by Heart deficiency with fire agitation, some by Liver deficiency with gallbladder timidity, some by fluid retention below the Heart. Fire fears water, hence palpitation occurs. Rehmannia can communicate between Heart and Kidney, benefit Liver and Gallbladder, and promote diuresis, thus treating these conditions). It treats fatigue and drowsiness. Chest and epigastrium stuffiness and oppression (If caused by dryness-fire of Liver and Gallbladder closing off in the Stomach, it should be used together with *Danggui Shen* [Radix Angelicae Sinensis Stem]). Epistaxis, hematemesis, hematuria (Painful urination with blood is *Xuelin* [Blood Strangury]; painless is hematuria). Syncope due to blood loss, metrorrhagia and metrostaxis (The *Neijing* states: "Yin deficiency with Yang hyperactivity is termed Metrorrhagia"). Regulates menstruation and calms the fetus. Promotes urination and bowel movements.
Nature is cold and moistening. Contraindicated in Spleen deficiency leading to diarrhea and Stomach deficiency leading to poor appetite. The best quality comes from Huaiqing, characterized by being plump, short, glutinous flesh, fine skin, and a chrysanthemum-heart pattern in the cross-section. Use those that sink in water; do not use those that float. Incompatible with *Beimu* [Fritillariae Bulbus]. Averse to *Wuyi* [Myrobalan]. Avoid Radish (*Lafu*), scallion, garlic, and copper/iron vessels. Harmonizes well with *Mendong* [Ophiopogonis Radix], *Danpi* [Moutan Cortex], and *Danggui* [Angelicae Sinensis Radix].
Gently tonifies Liver and Kidney, nourishes Blood and Yin.
Sweet and slightly warm. Enters the Foot-Sanyin Meridians (Liver, Spleen, Kidney). Nourishes Kidney Water, fills marrow, unblocks blood vessels, tonifies True Yin. Improves hearing and vision (Ears are the orifices of the Kidney; Eyes are the orifices of the Liver. Eyes see when nourished by Blood; Ears hear when nourished by Blood). Darkens hair and beard. Also tonifies Spleen Yin and stops chronic diarrhea (The *Neijing* states: "The Kidney governs the two orifices. Chronic diarrhea often belongs to Kidney deficiency. Moreover, excessive diarrhea consumes Yin; thus, one should tonify the Kidney, not solely blame the Spleen"). Treats consumptive injuries, wind-bi syndromes. Fever due to Yin deficiency. Dry cough with scanty sputum (For coughs due to Yin deficiency, *Dihuang Wan* [Rehmannia Pill] is the essential medicine, which also resolves phlegm. Zhu Danxi said: "In chronic illness, ministerial fire rises, fluids condense into phlegm rather than generating Blood. One should nourish Blood to control ministerial fire, and the phlegm will resolve naturally." Yu Jiayan said: "For coughs progressing to hyperventilation and sweating, if the lower body is not tonified but only the upper body cleared, it will inevitably lead to Qi collapse and sudden death. This is the fault of the physician.") Shortness of breath and panting (*Zhenyuan Yin* [True Origin Decoction]: 1 liang of Shudihuang, 3 qian of Dangguishen, 1 qian of Zhi Gancao. Treats shortness of breath resembling asthma, rapid breathing, inability to lift Qi upward or descend it downward, airway obstruction, in critical condition. Laypeople know only of Qi urgency, thinking the disease is in the upper body, unaware that the root lies in the empty Sea of Qi, with Liver-Kidney depletion, representing a failure of Zi-Wu intersection, a Qi collapse syndrome. This is most common in women with chronic Blood Sea deficiency. This decoction should be used to rescue and soothe. If ignorant physicians mistakenly diagnose phlegm reversal and Qi stagnation, using pills like Niuhuang Suhexiang or Qi-breaking agents like Qingpi, Chenpi, Zhike, it will accelerate danger.) Empty feeling in the Stomach with hunger. Acne/pox lacking pus due to Blood deficiency. Soreness and pain in calves and thighs after illness. Urgent abdominal pain postpartum (Zhu Danxi said: "During pregnancy, clearing heat and nourishing Blood should be primary. Postpartum, greatly tonifying Qi and Blood is appropriate. Even with other complications, they should be treated secondarily.") Yin deficiency in exterior contraction syndromes. Anhidrosis and constipation (When Yin Qi overflows externally, sweat is produced; when Yin Blood moistens internally, bowels move). Various types of bleeding disorders. All cases of Liver-Kidney Yin deficiency and various deficiency consumptions. It is the primary herb for strengthening Water to control Fire.
However, for individuals with Qi stagnation, it may obstruct the chest and epigastrium. Use with caution (Guo Peilan's *Bencao Hui* quotes Zhu Danxi: "Qi disorders are harmless." Not knowing that Blood tonics are Yin in nature and possess a cloying/stagnant character. Overuse by those with weak Stomach Qi leads to fullness and reduced appetite, hindering recovery. Zhang Jingyue's *Quan Shu* states: "Rehmannia grows in fertile central lands, absorbing the strongest Earth Qi. Its yellow color corresponds to Earth; its sweet taste corresponds to Earth. I cannot believe it is not a herb for the Middle Jiao (Spleen/Stomach). However, the Spleen/Stomach prefers warmth and dislikes cold. Raw Dihuang is cold, disliked by the Spleen/Stomach. After thorough steaming and drying, it becomes sweet and warm, suitable for the Spleen/Stomach. Yet, Shudihuang is a Yin-cloying and stagnant herb, highly unsuitable for Spleen/Stomach diseases)."
Method for preparing Shudihuang (Prepared Rehmannia Root): Select dozens of jin of plump Rehmannia roots that sink in water. Wash away sand and soil. Sun-dry slightly. Separately take dozens of jin of smaller, thinner roots, crush and press to extract juice. Pour into stone vessels, soak until fully penetrated. Place in a willow-wood steamer set over a clay pot. Steam for one day, then sun-dry for several days until extremely dry. Repeat steaming and drying nine times. Any residual juice dripping into the pot must also be mixed and dried until completely dry. The resulting Rehmannia is glossy black like lacquer, sweet as malt syrup. Store in porcelain jars because its oily texture prefers moisture. (Note: Rehmannia is chosen for its pure Yin, quiet, and heavy nature. Recently, many mix it with good wine and Amomum seed powder before steaming and drying, which disrupts its nature with dispersing, aromatic, and drying properties—a very poor method. Some stir-fry with ginger juice, which is even more inappropriate. Currently, market sellers simply boil it once and sell it, causing immeasurable harm. Rehmannia inherits the pure Yin and extreme cold nature of the North. Without frequent refining by Sun and fierce fire, it does not become warm. Therefore, in *Guben Gao* [Solidify Root Paste], although boiled for days, raw and prepared Rehmannia are used half-and-half. If raw Rehmannia is boiled once and used as prepared Rehmannia in formulas like *Guishen Wan*, *Yougui Wan*, *Qijun Zi*, or *Bajun Zi*, the cold-nature remains unremoved. Since Heart and Kidney meridians differ, using a Heart-meridian cold herb as Sovereign and Kidney-meridian warm herbs as Ministers/Assistants is not only useless but draws cold down to damage True Yang. Those with slight deficiency may tolerate it temporarily; those with severe deficiency and cold face isolated Qi and peril. Such improper processing causes severe harm, which is the worst outcome. Market doctors sometimes charred Shudihuang and Gouqi, turning sweet-moist Yin-nourishing herbs into bitter-dry Yin-damaging substances. This is not only useless but harmful.)