生地，味苦甘，气寒，沉也，阴也。入手少阴及手太阴。凉头面之火，清肺肝之热，亦
君药
也。其功专于凉血止血，又善疗金疮，安胎气，通经，止漏崩，俱有神功。但性寒，脾胃冷
者不宜多用。夫生地既善凉血，热血妄行，或吐血、或衄血、或下血，宜用之为君，而加入
荆
芥以归其经，加入三七根末以止其路，又何热之不除而血之不止哉。然而此味可多用而不可
频用，可暂用而不可久用也。当血之来也，其势甚急，不得已重用生
地，以凉血而止血。若血一止，即宜改用温补之剂，不当仍以生地再进也。今人不知其故，
惊生地止血之神，视为灵丹妙药，日日煎服，久则脾胃太凉，必至泄泻，元气困顿，而血又
重来。不悟生地用多，反疑生地用少，仍然更进，且有增其分两，至死而不悟者，亦可悲也
夫。
或问生地与熟地同是一物，而寒温各别，入汤煎服，非生地变为熟地耶？曰∶生地不先
制为
熟，则味苦，苦则凉。生地已制为熟，则味甘，甘则温，何可同日而语。譬如一人，先未陶
淑，其性刚，后加涵养，其性柔，生熟地何独不然。
或问生地凉血以止血，是生地实救死妙药也。吾见世人服生地以止血，不敢再用，改用
他药
，而仍然吐血，一服生地而血又即止，安在生地之不宜久服乎？曰∶服生地止血之后，改用
他药，而仍吐血者，非不用生地之故，乃改用他药。不得其宜之故耳。夫止血之后，不可不
补血，然而补血实难。补血之药，未有不温者，而吐血之后，又最忌温，恐温热之性引沸其
血也。补血之药，又未有不动者，而吐血之后，又最忌动，恐浮动之气又催迫其血也。然则
用生地止血，当用何药以善其后乎？六味地黄汤加五味、麦冬，则平而不热，静而不动，服
之则水升火降，永无再犯之忧，又安在生地之必宜服哉。
或疑生地虽凉，要亦不甚，以治虚热之病，似应相宜，何禁用甚严也？不知生地之凉，
不特
沁入于胃，且沁入于脾，不特沁入于脾，又沁入于肾。故久服则脾肾俱伤，往往致大瘕之泻
，不可不慎用也。
或疑生地止血甚神，而泻中有补，似亦与元参之类可齐驱而并驾也。然而元参尚可重用，
而
生
地断宜轻用也。盖生地沉阴之性，凉血是其所长，退火是其所短，不比元参既退浮游之火，
而又滋枯涸之水也。生地凉血，则血虽止而不行。生地不能退火，则火欲炎而难静，久则火
上腾而血亦随沸矣。
或疑生地寒凉，可以止血，以血得寒而止乎。抑血得补而止乎？夫生地凉中有补，血得
凉而
止，亦得补而止也。盖血非凉则无以遏其上炎之势，非补亦无以投其既济之欢，故生地止血
建功实神者，正以凉中有补也。
或疑生地清肺肝之热，肺肝俱属阴，补阴即不能奏功之速，自宜久服之为得，安在生地
只可
暂用而不可常服耶？曰∶生地清肺肝之热，亦只清一时之热耳。肺肝之火，初起多实，久病
多虚。生地清初起之热，则热变为寒；清久病之热，则热愈增热。盖实火得寒而势解，虚火
得寒而焰起也。故生地只可一时暂用，而断断不可长用耳。
生地黄，味道苦、甘，性质寒凉，质地沉降，属于阴药。它归入手少阴心经和手太阴肺经。它能清降头面部的火热，清除肺脏和肝脏的热邪，也可以作为君药（方剂中起主要治疗作用的药物）使用。它的功效专门在于凉血止血，又擅长治疗金创（金属利器造成的创伤），安胎气，通经络，止漏下和崩漏，都有神奇的疗效。但是因为它性寒，脾胃虚寒的人不适宜多用。既然生地黄善于凉血，对于热血妄行导致的吐血、鼻衄（鼻出血）、便血等症，应当用它作为君药，并加入荆芥以引导血液回归经脉，加入三七根末以阻断出血的路径，这样还有什么热不能消除、血不能止住的呢？然而这味药可以多用但不可频繁使用，可以暂时使用但不可长期使用。当出血发生时，病势非常急迫，不得已才重用生地黄，来凉血止血。如果血一旦停止，就应当改用温补的药剂，不应当再用生地黄继续服用。现在的人不知道其中的缘故，惊叹于生地黄止血的神奇，把它视为灵丹妙药，每天煎服，时间久了导致脾胃过于寒凉，必然导致泄泻，元气困顿，而血又会重新再来。不明白生地黄用多了反而怀疑生地黄用得少，仍然增加剂量，甚至有加重分量直到死亡都不醒悟的，真是可悲啊。
有人问：生地黄和熟地黄本是同一物，但寒温性质各不相同，在汤剂中煎服，难道不是生地黄变成了熟地黄吗？回答说：生地黄如果不先加工制成熟地黄，味道就是苦的，苦味则性凉。生地黄如果已经加工制成熟地黄，味道就是甘的，甘味则性温，这两者怎么可以相提并论呢？这就好比一个人，先前没有经过陶冶修养，性格刚烈；后来加以涵养，性格变得柔和，生地黄和熟地黄的区别难道不是这样吗？
有人问：生地黄凉血以止血，确实是救死的妙药。我看见世人服用生地黄止血后，不敢再用了，改用其他药物，结果仍然吐血，一服用生地黄血又立即停止，这怎么能说生地黄不适宜久服呢？回答说：服用生地黄止血之后，改用其他药物，却仍然吐血的，不是因为没使用生地黄的原因，而是改用的其他药物不得当的缘故。止血之后，不可以不补血，然而补血确实很难。补血的药物，没有不温热的，而在吐血之后，最忌讳温热，恐怕温热的性质会引动沸腾的血液。补血的药物，又没有不流动的，而在吐血之后，又最忌讳流动，恐怕浮动的气机又会催迫血液外溢。那么，使用生地黄止血后，应当用什么药物来善后呢？用六味地黄汤加五味子、麦冬，则性质平和而不热，安静而不流动，服用它则肾水上升心火下降，永远不再有复发的忧虑，这又何必执着于必须服用生地黄呢？
有人怀疑：生地黄虽然性凉，但也并不十分寒凉，用来治疗虚热之病，似乎应该适宜，为什么禁止得这么严格呢？不知道生地黄之凉，不仅渗入胃中，而且渗入脾中，不仅渗入脾中，又渗入肾中。所以长期服用则会损伤脾肾，往往导致严重的泄泻（大瘕之泻），不可不谨慎使用。
有人怀疑：生地黄止血很神奇，而且在泻中有补，似乎也可以与玄参之类齐名并驾。然而玄参还可以重用，而生地黄断然适宜轻用。因为生地黄具有沉阴的性质，凉血是它的长处，退火是它的短处，不像玄参既能退去浮游之火，又能滋润枯涸之水。生地黄凉血，则血虽然停止但不运行；生地黄不能退火，则火想要炎上而难以平静，时间久了火向上腾越，血也会随之沸腾。
有人怀疑：生地黄寒凉，可以止血，是因为血遇到寒凉而停止吗？还是因为血得到补益而停止？生地黄凉中有补，血得到凉而停止，也得到补而停止。大概血不凉就无法遏制其上炎的趋势，不补也无法投合其既济的欢悦，所以生地黄止血建功确实神奇，正是因为凉中有补。
有人怀疑：生地黄清肺肝之热，肺肝都属于阴，补阴就不能奏效迅速，自然适宜长期服用才算得当，为什么说生地黄只可暂时使用而不可常服呢？回答说：生地黄清肺肝之热，也只清除一时的热邪罢了。肺肝之火，初起多属实证，久病多属虚证。生地黄清除初起的实热，则热变为寒；清除久病的虚热，则热更增热。大概实火遇到寒凉则势头解除，虚火遇到寒凉则火势燃起。所以生地黄只可一时暂时使用，断断不可长期使用。
Shengdi (Rehmanniae Radix), with a bitter and sweet taste, is cold in nature, heavy in quality, and belongs to the Yin category. It enters the Hand-Shaoyin Heart Meridian and the Hand-Taiyin Lung Meridian. It cools down fire in the head and face, clears heat from the Lungs and Liver, and can also serve as the Jun Herb (the principal herb in a prescription). Its efficacy specializes in cooling blood and stopping bleeding; it is also adept at treating metal wounds, stabilizing fetal Qi, unblocking meridians, and stopping metrorrhagia and uterine bleeding, all with miraculous effects. However, due to its cold nature, it is not suitable for frequent use by those with cold Spleen and Stomach. Since Shengdi excels at cooling blood, for conditions where hot blood moves recklessly, resulting in hematemesis (vomiting blood), epistaxis (nosebleed), or lower body bleeding, it should be used as the Jun Herb. By adding Jingjie (Schizonepetae Herba) to guide blood back into the vessels, and adding Sanqi root powder (Notoginseng Radix et Rhizoma) to block the bleeding pathway, what heat would remain uneliminated and what bleeding would fail to stop? Nevertheless, this herb can be used in large doses but not frequently; it can be used temporarily but not for a long duration. When bleeding occurs, the condition is often urgent, necessitating the heavy use of Shengdi to cool blood and stop bleeding. Once the bleeding stops, one should switch to warming and tonifying formulas, rather than continuing with Shengdi. People today do not understand this principle; amazed by Shengdi's miraculous hemostatic effect, they regard it as a panacea, decocting and taking it daily. Over time, this causes the Spleen and Stomach to become too cold, inevitably leading to diarrhea, exhaustion of Yuan Qi (Original Qi), and the recurrence of bleeding. They fail to realize that excessive use of Shengdi leads them to suspect insufficient dosage, causing them to increase the dose further, even up to death without awakening, which is truly pitiable.
One asks: Shengdi and Shudi (Prepared Rehmanniae Radix) are from the same source, yet their cold and warm natures differ. Does Shengdi transform into Shudi when decocted in soup? The answer is: If Shengdi is not processed into Shudi beforehand, its taste is bitter, and bitterness implies coldness. If Shengdi has been processed into Shudi, its taste becomes sweet, and sweetness implies warmth. How can they be compared? It is like a person: initially unrefined, their nature is rigid; after cultivation and nurturing, their nature becomes gentle. Is it not so for Shengdi and Shudi?
One asks: Shengdi cools blood to stop bleeding, making it a miraculous drug for saving lives. I see people who, after using Shengdi to stop bleeding, dare not use it again and switch to other herbs, yet still vomit blood. However, upon taking Shengdi, the bleeding stops immediately. How can it be said that Shengdi is unsuitable for long-term use? The response is: After stopping bleeding with Shengdi, if switching to other herbs results in continued hematemesis, it is not because Shengdi was not used, but because the substituted herbs were inappropriate. After stopping bleeding, blood must be replenished, but this is difficult. Blood-tonifying herbs are invariably warm, yet after hematemesis, warmth is most contraindicated, as warm properties may agitate the boiling blood. Blood-tonifying herbs are invariably moving, yet after hematemesis, movement is most contraindicated, as moving Qi may urge blood to flow out. So, after using Shengdi to stop bleeding, what herb should be used for follow-up treatment? Liuwei Dihuang Wan (Six-Ingredient Pill with Rehmannia) added with Wuweizi (Schisandrae Fructus) and Maidong (Ophiopogonis Radix) is neutral and not hot, calm and non-moving. Taking it causes Kidney Water to rise and Heart Fire to descend, eliminating the worry of recurrence. Why insist on the necessity of taking Shengdi?
One doubts: Although Shengdi is cool, it is not extremely cold. It seems suitable for treating deficiency-heat diseases, so why is its prohibition so strict? One does not know that Shengdi’s coolness penetrates not only the Stomach but also the Spleen, and not only the Spleen but also the Kidneys. Therefore, long-term use damages both the Spleen and Kidneys, often leading to severe diarrhea (Da Jia Zhi Xie), so it must be used with caution.
One doubts: Shengdi’s hemostatic effect is miraculous, and it contains tonification within its purging action, seemingly comparable to Xuanshen (Scrophulariae Radix). However, Xuanshen can be used in heavy doses, whereas Shengdi should strictly be used in light doses. This is because Shengdi has a sinking and Yin nature; cooling blood is its strength, while clearing fire is its weakness. Unlike Xuanshen, which clears floating fire and nourishes dried-up fluids, Shengdi cools blood so that although bleeding stops, circulation halts. Shengdi cannot clear fire, so fire tends to flare up and remains restless; over time, fire rises upward, and blood boils along with it.
One doubts: Shengdi is cold and cool, capable of stopping bleeding. Is it because blood stops when cooled? Or because blood stops when tonified? Shengdi is cool yet contains tonification; blood stops when cooled and also when tonified. Blood requires coolness to curb its flaming upward trend, and it requires tonification to achieve harmonious balance (Ji Ji). Thus, Shengdi’s miraculous hemostatic achievement lies precisely in its combination of cooling and tonification.
One doubts: Shengdi clears heat from the Lungs and Liver. Since both Lungs and Liver belong to Yin, and Yin tonification acts slowly, long-term use seems appropriate. Why is it said that Shengdi can only be used temporarily and not commonly? The answer is: Shengdi clears heat from the Lungs and Liver only for a temporary period. Lung and Liver fire is mostly excess in the early stages and mostly deficiency in chronic illness. Shengdi clears initial excess heat, transforming heat into cold; however, clearing chronic deficiency heat increases heat further. Excess fire subsides with cold, but deficiency fire flares up with cold. Therefore, Shengdi can only be used temporarily for a short time and must absolutely not be used for a long duration.