山中古松。久为人斩伐。其枯折槎 。枝叶不复上生者。谓之茯苓拨。即于四面丈
余地内。以铁锥刺地。如有茯苓。则锥固不可拔。乃掘取之。其拨大者。茯苓亦大。（颂）
甘淡而平。气味俱薄。浮而升。阳也。东垣曰。降也。阳中之阴。（甘和而淡。淡为天
之阳。其性上行生津液。开腠理。滋水之源。而下降通水道。二说固相合。）白者入手太阴
足太阳气分。赤者入足太阴手少阴太阳气分。补心益脾。白优于赤。通利小肠。赤亦胜白。
（仲淳）诸本草和中益气。除湿理脾。调脏气。开腠理。逐水准火。生津导气。开胸腑。治
胸胁逆气。心下结痛。安心神。止忧恚惊悸。消痰润肺。止咳逆。利胸中痰水。愈消渴及呕
吐。并大肠淋沥。水肿淋结。伐肾邪长阴。治肾积奔豚。利腰膝间血。疗遗精白浊。酒浸。
与光明朱砂同用。能秘童元。（海藏）茯苓补虚劳。多在心脾之有准。（东垣）小便多者能止。
结者能通。（又）伐肾邪者。小便数能止之。小便涩能利之。与车前子相似。虽利小便而不
走气。（海
伐肾邪。取其淡而利窍。以平其气也。（类明）茯苓分阴阳而导湿。盖病于湿则阴阳混淆。
升降之职不行焉。茯苓气薄。为阳中之阴。上行导气。下行利水。故阴阳分判。而湿淫平也。
（又）茯苓利水。何又生津。讵知清阳上布。故浊阴下行。而气乃化。津乃生。经曰。脾主
为胃行其津液。是岂脾无真阳之运化。而能生胃中之津液哉。即此可悟茯苓除湿之义。凡药。
气重者主气
亦能补虚固肾。（文清）成于阴而生于阳。得老松之气浓。其质阴也。其气阳也。感土水之
气而成质。故其味甘平。补中利窍。补中则心脾实。利窍则邪热解。有补有泻之药也。（仲
淳）其治上焦或同于益真气者。以致阳而布其升清之化。或同于祛痰行气者。即于升清阳中
以达其浊阴之降。治下焦或同于分理导水者。达阴而致其降浊之化。或同于健脾和气者。即
降浊阴中以还其清阳之升。未可徒以下渗概之也。取白者。蒸晒三次。为末。以牛乳汁和膏
服之。或蜜浸。或酒浸。封固。百日后常服。不饥延年。肠化为筋。通神致灵。入五苓散。
利水除湿。暑气胜。则去桂。入六味丸。能伐肾邪。入补心丹。则补心安魂养神。得人参白
术橘皮山药扁豆芍药甘草。为补脾胃之上药。得二术泽泻车前白芍橘皮木瓜猪苓。为消水肿
之要剂。胸胁气逆胀满。茯苓一两。人参五钱。每服三钱。日三服。血虚心汗。（独心孔有
汗。别处无。）思虑多则汗亦多。宜养心血。以艾汤调茯苓末。日服一钱。浊遗带下。丈夫
元阳虚惫。精气不固。小便下浊。余沥常流。梦寐多惊频遗。并治妇人白淫白带。白茯苓去
皮四两作匮。以猪苓四钱半入内。煮二十余沸。取出日干。择去猪苓。为末。化黄蜡搜和。
丸弹子大。每嚼一丸。空心津下。以小便清为度。忌米醋。小便淋沥不禁。由心肾俱虚。神
志不守。白赤茯苓等分为末。以新汲水 洗去筋。控干。用酒煮地黄汁。捣膏搜和。丸弹子
大。每嚼一丸。空心盐酒下。消渴。由于上盛下虚。心火炎烁。肾水枯涸。不能交济而成。
白茯苓黄连各一斤。为末。熬天花粉作糊。丸梧子大。每温汤下五十丸。按世俗恒言茯苓淡
渗。观上数方。则补益心肾良多。且其用又似补阴为多。李氏所谓味重主血。义不谬也。
〔论〕 茯苓本古松灵气沦结成形。之颐谓其精英不发于枝叶。而返旋生气吸伏于踵。
所谓真人之息也。夫松秉真阳之性。凌冬不凋。乃其入土久而结茯苓。即根极至阴之下。而
真阳之凝结。更有如斯者。隐居言其性无朽蛀。埋地中三十年。色理无异。不可想见其真阳
之贞固哉。第其味淡。淡写天之阳。阳当上行。而气之薄者。为阳中之阴。又宜利水而下泄。
总
其气和。实和于至阴以归至阳。故始终惟有一淡。（海藏谓茯苓甘平。如何是渗利。兹举阳
吸阴阴归阳之义。以实甘平。然后知海藏之说不妄。盖甘具五味。平具五气。乃阴阳之合也
。）然淡本于甘。则阴阳相含之真气。已入中土而神其清浊之升降矣。诸本草谓其和中益
气。除湿理脾。逐水准火。（水火即阴阳之气所化。清阳不升。则郁而为火。浊阴不降。则
郁而为水。茯苓气阳质阴。合于水火之升降。但其味至淡。不能专功耳。）调脏气。开腠理
者。是在中土而致其清阳之气于上也。即其致清阳于上。而导浊阴于下者。亦此也。更宜究
者。清浊本之阴阳。阴阳兆于水火。水火赋之心肾。如甄权所谓善安心神。与本经忧恚惊悸
之治合。如好古所谓秘精。亦与别录长阴。日华子暖腰膝之义不远。然则用茯苓者。不得徒
守淡渗之说。而当思其从阳吸阴。吸阴归阳之元机矣。至所云安心神。秘精气。请更悉之。
心内阴而外阳。肾内阳而外阴。内者是神是主。外者是气是用。经曰。阳中之太阳心也。惟
茯苓禀真阳之粗气。却能吸阳中之阴以归阳。（阳中之阴为血。血者神气也。）是其能益心血
者也。阴既得宅于阳中。则神定而气充。是又谓之益心气耳。秘精之说。亦不外此。总之。
在上者阴宅于阳中。则火有主而下交于水。即得水中之火。从地气而蛰藏。在下者阳宅于阴
中。则水有主而上交于火。即得火外之水。从天气而发育。此所谓神足而气充。气充而精盈
。精盈而气固者也。
虚而上有痰火。下有湿热者。最宜。若劳役阳虚。小便多汗多者。禁用。（文清）衍义
补遗谓阴虚者。未宜。小便素利者。过服助燥损明。嵩言兼补阴之剂。可用。但不宜入燥剂
中耳。非比猪苓一味。诚为淡渗。阴虚者。当忌之。
〔修治〕 坚白者良。去皮。更宜水飞去筋。若误服之。令人眼中童子并黑睛点小。兼
盲目
山中古老的松树，长久以来被人砍伐。那些枯死折断、枝叶不再向上生长的部分，被称为“茯苓拨”。就在距离树干四周一丈多的地方，用铁锥刺入地面，如果这里有茯苓，铁锥就会固定住拔不出来，于是挖掘取出它。茯苓拨大的，茯苓也就大。（苏颂）
茯苓味甘淡，性平，气味都很淡薄，性质轻浮而上升，属于阳。李东垣说：它是下降的，是阳中之阴。（甘味调和而淡味渗利，淡味代表天之阳，其性质上行能生津液、开泄腠理；同时又能滋补水之源并向下通利水道。这两种说法原本就是相合的。）白色茯苓进入手太阴肺经和足太阳膀胱经的气分；红色茯苓进入足太阴脾经、手少阴心经和足太阳膀胱经的气分。它能补心益脾，白色优于红色；它能通利小肠，红色也胜过白色。（陈实功）
各种本草书籍认为它能和中益气，除湿理脾，调理脏气，开泄腠理，驱逐水邪平抑火邪，生津导气，开通胸腑，治疗胸胁逆气、心下结痛，安定心神，止忧恚惊悸，消痰润肺，止咳逆，利胸中痰水，治愈消渴及呕吐，以及大肠淋沥、水肿淋结，伐除肾邪、促进阴长，治疗肾积奔豚，利腰膝间血，疗治遗精白浊。（张元素）用酒浸泡，与光明朱砂同用，能固秘童真元阳。（张元素）茯苓能补虚劳，主要作用于心脾，这是有定论的。（李东垣）小便多者它能止住，小便闭塞者它能通利。（又）所谓伐除肾邪，是指小便频数时它能止之，小便涩滞时它能利之。这与车前子相似，虽然利小便却不耗散正气。（张元素）
伐除肾邪，是利用其淡味以通利窍道，从而平复肾气。（赵以德）茯苓分阴阳而引导湿气。大概因为湿邪致病会导致阴阳混淆，升降的功能无法行使。茯苓气薄，属于阳中之阴，上行引导气机，下行通利水道，因此阴阳得以分辨，湿淫得以平息。（又）茯苓既能利水，为何又能生津？要知道清阳之气上布，所以浊阴之气下行，气才能化生，津液才能产生。《内经》说：脾主为胃运行津液。这难道不是依靠脾的真阳运化功能，才能生成胃中的津液吗？由此可以领悟茯苓除湿的意义。凡是药物，气味厚重的主要作用于气，也能补虚固肾。（王好古）茯苓成于阴而生于阳，得老松之气浓厚，其质地属阴，其气属阳，感受土水之气而成质，所以味道甘平。补中则心脾充实，利窍则邪热解除，是一种既有补益又有泻利的药物。（陈实功）
它治疗上焦病症，有时如同益真气那样，通过提升阳气来发挥升清的作用；有时如同祛痰行气那样，在升发清阳的同时达到降泄浊阴的目的。治疗下焦病症，有时如同分理导水那样，通达阴气以实现降浊的作用；有时如同健脾和气那样，在降泄浊阴的同时恢复清阳的升发。不能简单地将其功效概括为下渗。选取白色茯苓，蒸晒三次，研为粉末，用牛乳汁调和成膏服用；或者用蜂蜜浸渍，或者用酒浸渍，密封保存，百日之后常服，可以不饥饿、延年益寿，肠道化为筋脉，通神致灵。
加入五苓散，能利水除湿。暑气盛时，去掉桂枝。加入六味丸，能伐除肾邪。加入补心丹，则能补心安魂养神。与人参、白术、橘皮、山药、扁豆、芍药、甘草配合，成为补脾胃的上等药物。与苍术、白术、泽泻、车前子、白芍、橘皮、木瓜、猪苓配合，成为消除水肿的重要方剂。胸胁气逆胀满，用茯苓一两，人参五钱，每次服用三钱，每日三次。血虚导致的心汗（只有心脏部位出汗，别处无汗），思虑过多则汗也多，适宜滋养心血，用艾汤调服茯苓末，每日服用一钱。
男子元阳虚惫，精气不固，小便浑浊，余沥常流，梦中多惊频繁遗精，以及妇人白淫白带，可用白茯苓去皮四两做成容器，将猪苓四钱半放入其中，煮二十多沸后取出晒干，拣去猪苓，研为粉末，用黄蜡融化调和，制成弹子大小的丸药。每次嚼服一丸，空腹用唾液送下，以小便清澈为度，忌食米醋。
小便淋沥不禁，是由于心肾俱虚，神志不守。将白茯苓、赤茯苓等分为末，用新汲水洗去筋膜，控干水分，用酒煮地黄汁捣膏调和，制成弹子大小的丸药。每次嚼服一丸，空腹用盐酒送下。
消渴，是由于上盛下虚，心火炎烁，肾水枯涸，不能相互交济而成。用白茯苓、黄连各一斤，研为粉末，熬天花粉作糊，制成梧桐子大小的丸药。每次温开水送下五十丸。
按世俗恒言，茯苓淡渗。看上述几个方子，可知它对补益心肾良多，而且其用法似乎偏重于补阴。李氏所说的“味重主血”，道理是不谬的。
〔论述〕 茯苓本是古松灵气沦陷凝结而成的形体。缪希雍认为它的精华不发泄于枝叶，而是回旋生气吸伏于根部。这就是所谓的“真人之息”。松树秉受真阳的性质，凌冬不凋，但它入土久而结成茯苓，即使扎根于极阴之下，真阳的凝结竟有如此情况。隐居（陶弘景）说它的性质不会腐朽蛀蚀，埋在地下三十年，色泽纹理没有变化，不可想象其真阳的贞固啊。只是它的味道淡，淡写天之阳，阳应当上行，但因为它气薄，属于阳中之阴，又适宜利水而下泄。总的来说，它的气和，实际上是和于至阴以归于至阳，所以始终只有一个“淡”字。（张元素说茯苓甘平，怎么说是渗利呢？这里列举了阳吸阴、阴归阳的道理，来证实甘平的实质，然后才知道张元素的说法没有妄言。盖甘具五味，平具五气，乃是阴阳的结合。）然而淡本源于甘，那么阴阳相含的真气，已经入中土而神奇地调节清浊的升降了。各种本草书说它能和中益气，除湿理脾，逐水准火。（水火即阴阳之气所化，清阳不升，则郁而为火；浊阴不降，则郁而为水。茯苓气阳质阴，契合水火之升降，只是它的味道至淡，不能单独起专功罢了。）调理脏气，开泄腠理，是在中土将清阳之气引向上方。即它引导清阳于上，同时导引浊阴于下，也是这个原理。更应探究的是，清浊本源于阴阳，阴阳兆始于水火，水火禀赋于心肾。如甄权所说善于安心神，与本经治疗忧恚惊悸相符；如好古所说秘精，也与《别录》长阴、日华子暖腰膝的意思不远。那么使用茯苓的人，不得仅仅坚守淡渗的说法，而应当思考它从阳吸阴、吸阴归阳的根本机理。至于所说的安心神、秘精气，请再详细说说。
心内阴而外阳，肾内阳而外阴。内部是神、是主，外部是气、是用。《内经》说：阳中之太阳是心。只有茯苓禀受真阳的粗气，却能吸收阳中之阴以归于阳。（阳中之阴即为血，血即是神气。）所以它能补益心血。阴既然得以宅居于阳中，则神定而气充，这又叫做益心气。秘精的说法，也不外乎此理。总之，在上者阴宅于阳中，则火有主而下交于水，即得水中之火，从地气而蛰藏；在下者阳宅于阴中，则水有主而上交于火，即得火外之水，从天气而发育。这就是所谓神足而气充，气充而精盈，精盈而气固。
虚证而上有痰火，下有湿热者，最适宜。如果是劳役导致的阳虚，小便多、汗多者，禁用。（王好古）《衍义补遗》说阴虚者不宜。小便素来通畅者，过服会助燥损明。嵩（可能是指某位医家或泛指）说兼补阴的药剂可以使用，但不宜放入燥剂中罢了。不像猪苓一味，诚然是淡渗，阴虚者应当禁忌。
〔修治〕 坚硬白色的品质好。去皮，更宜用水洗去筋膜。如果误服，会让人眼中瞳仁和黑睛出现小黑点，甚至导致盲目。
Ancient pines in the mountains, having been felled by humans for a long time. The withered and broken parts where branches and leaves no longer grow upward are called "Fuling Bo" (Fuling stalk). Within an area more than one zhang away from the four sides of the trunk, use an iron awl to pierce the ground. If there is Poria here, the awl will become fixed and cannot be pulled out; then dig it up. Where the Fuling Bo is large, the Poria is also large. (Su Song)
Poria has a sweet and bland taste and is neutral in nature. Its aroma and flavor are both thin. It is light and ascending, belonging to Yang. Li Dongyuan said: It descends; it is Yin within Yang. (Sweetness harmonizes and blandness promotes diuresis; blandness represents the Yang of Heaven. Its nature ascends to generate fluids and open the interstices; simultaneously, it nourishes the source of water and descends to unblock the water passages. These two theories are originally consistent.) White Poria enters the Qi level of the Hand Taiyin Lung Meridian and Foot Taiyang Bladder Meridian. Red Poria enters the Qi level of the Foot Taiyin Spleen Meridian, Hand Shaoyin Heart Meridian, and Foot Taiyang Bladder Meridian. It tonifies the Heart and benefits the Spleen; white is superior to red. It promotes urination and unblocks the small intestine; red also surpasses white. (Chen Shigong)
Various Materia Medica texts state that it harmonizes the middle and benefits Qi, removes dampness and regulates the Spleen, adjusts Zang organ Qi, opens the interstices, expels water pathogens and calms fire, generates fluids and guides Qi, opens the chest and epigastrium, treats rebellious Qi in the chest and hypochondrium, pain and knotting below the heart, calms the Spirit, stops worry, resentment, fright, and palpitations, resolves phlegm and moistens the Lungs, stops cough and rebellious Qi, benefits fluid retention in the chest, cures Xiao Ke (Wasting-Thirst) and vomiting, as well as dribbling of the Large Intestine, edema and strangury, attacks Kidney pathogens and promotes genital growth, treats Kidney accumulation and Ben Tun (rushing gas), benefits blood in the waist and knees, treats spermatorrhea and leukorrhea. (Zhang Yuansu) Soaked in wine and used together with Guangming Cinnabar (Zhusha), it can secure the primal Yuan energy of youth. (Zhang Yuansu) Poria can tonify deficiency and exhaustion, with its effects primarily on the Heart and Spleen, which is a settled conclusion. (Li Dongyuan) It can stop frequent urination and unblock obstruction. (Again) To attack Kidney pathogens means stopping frequent urination when it occurs, and promoting urination when it is difficult. This is similar to Semen Plantaginis (Cheqianzi); although it promotes urination, it does not deplete Zheng Qi (Upright Qi). (Zhang Yuansu)
Attacking Kidney pathogens relies on its blandness to open orifices and thereby calm Qi. (Zhao Yikui) Poria differentiates Yin and Yang to guide Dampness. Generally, disease caused by Dampness leads to confusion of Yin and Yang, causing the functions of ascent and descent to fail. Poria has a thin Qi and belongs to Yin within Yang; it ascends to guide Qi and descends to promote urination. Thus, Yin and Yang are distinguished, and excessive Dampness is pacified. (Again) How can Poria promote urination yet also generate fluids? One must know that when Clear Yang spreads upward, Turbid Yin descends downward. Only then can Qi transform and fluids be generated. The Classic says: The Spleen governs transporting and transforming fluids for the Stomach. Does this not rely on the true Yang transformation of the Spleen to generate fluids in the Stomach? From this, one can comprehend the meaning of Poria removing Dampness. Generally, herbs with heavy Qi and Flavor mainly affect Qi but can also tonify deficiency and secure the Kidney. (Wang Haogu) Poria forms through Yin and is born through Yang, obtaining the dense Qi of old pines. Its substance is Yin, and its Qi is Yang. It acquires its form by sensing the Qi of Earth and Water, hence its taste is sweet and neutral. Tonifying the middle solidifies the Heart and Spleen; opening orifices resolves pathogenic heat. It is a herb that possesses both tonifying and draining properties. (Chen Shigong)
When treating disorders of the Upper Jiao, it sometimes acts like herbs that benefit True Qi, raising Yang to exert its ascending and clearing transformation; or like herbs that dispel phlegm and move Qi, achieving the descent of Turbid Yin amidst the ascent of Clear Yang. When treating disorders of the Lower Jiao, it sometimes acts like herbs that differentiate and guide water, reaching Yin to effect its descending and turbid transformation; or like herbs that strengthen the Spleen and harmonize Qi, restoring the ascent of Clear Yang amidst the descent of Turbid Yin. Its effects cannot be simply summarized as downward seepage. Select white Poria, steam and sun-dry it three times, grind into powder, mix with ox milk to make a paste for oral administration. Or soak in honey, or soak in wine, seal tightly, and take regularly after one hundred days. This prevents hunger, prolongs life, transforms the intestines into sinews, connects to the Spirit, and brings agility.
Added to Wu Ling San (Five-Ingredient Powder with Poria), it promotes urination and removes Dampness. In cases of prevailing Summerheat, remove Ramulus Cinnamomi (Guizhi). Added to Liu Wei Di Huang Wan (Six-Ingredient Pill with Rehmannia), it attacks Kidney pathogens. Added to Bu Xin Dan (Heart-Tonifying Pill), it tonifies the Heart, calms the Soul, and nourishes the Spirit. Combined with Radix Ginseng (Renshen), Rhizoma Atractylodis Macrocephalae (Baizhu), Pericarpium Citri Reticulatae (Chenpi), Rhizoma Dioscoreae (Shanyao), Semen Dolichoris (Baidou), Radix Paeoniae Alba (Baishao), and Radix Glycyrrhizae (Gancao), it becomes a premier formula for tonifying the Spleen and Stomach. Combined with Rhizoma Atractylodis (Baizhu/Cangzhu), Radix Alismatis (Zexie), Semen Plantaginis (Cheqianzi), Radix Paeoniae Alba (Baishao), Pericarpium Citri Reticulatae (Chenpi), Fructus Chaenomelis (Mugua), and Polyporus (Zhu Ling), it becomes an essential preparation for eliminating edema. For rebellious Qi in the chest and hypochondrium causing distension and fullness, use 1 liang of Poria and 5 qian of Radix Ginseng (Renshen). Take 3 qian per dose, three times daily. For Heart Sweat due to Blood deficiency (sweating only from the heart region, nowhere else), excessive thinking leads to more sweating. It is suitable to nourish Heart Blood by taking Poria powder mixed with Mugwort decoction, 1 qian daily.
For men with deficient and exhausted Primal Yang, insecure Essence and Qi, turbid urine, constant post-void dribbling, frequent nocturnal emissions due to dreams and fright, and for women with Bai Yin (white discharge) and Dai Xia (leukorrhea): Use 4 liang of peeled white Poria as a container, place 4.5 qian of Polyporus (Zhu Ling) inside, boil for over twenty boils, take out, dry in the sun, remove Polyporus, grind into powder, mix with melted yellow beeswax, and roll into pills the size of a bullet. Chew one pill at a time, swallow with saliva on an empty stomach. Stop when urine becomes clear. Avoid rice vinegar.
For involuntary dribbling of urine due to deficiency of both Heart and Kidney and loss of Shen control: Mix equal parts of white and red Poria into powder. Wash with fresh well water to remove fibrous roots, drain, boil Radix Rehmanniae Preparata (Shudihuang) in wine to extract juice, mash into a paste, mix with the powder, and roll into pills the size of a bullet. Chew one pill at a time, swallow with salted wine on an empty stomach.
Xiao Ke (Wasting-Thirst) arises from excess above and deficiency below, blazing Heart Fire, and dried-up Kidney Water, failing to interact and balance each other. Use 1 jin each of white Poria and Cortex Phellodendri (Huanglian). Grind into powder, cook Radix Panacis Quinquefolii (Tianhuafen) to make a paste, and roll into pills the size of a wutong seed. Take fifty pills with warm water each time.
According to common secular sayings, Poria is bland and permeating. Observing the aforementioned formulas, it is evident that it greatly benefits and tonifies the Heart and Kidney, and its usage seems to lean more towards tonifying Yin. Li's statement that "heavy flavor governs Blood" is not incorrect.
[Discussion] Poria is formed by the condensation of the spiritual energy of ancient pines. Miao Xiyong stated that its essence does not emit through branches and leaves but returns to circulate vital Qi, absorbing it into the root. This is what is called the "breath of the perfected person." Pine possesses the nature of True Yang and does not wither in winter. Yet, upon entering the soil and forming Poria over time, even rooting in the deepest Yin, the condensation of True Yang occurs in such a manner. Ju Yin (Tao Hongjing) said its nature does not rot or get eaten by insects; buried in the ground for thirty years, its color and texture remain unchanged. One cannot imagine how steadfast its True Yang is. However, its taste is bland. Bland writes the Yang of Heaven. Yang should ascend, but because its Qi is thin, it belongs to Yin within Yang, making it suitable for promoting urination and descending. Overall, its Qi is harmonious, actually harmonizing with Extreme Yin to return to Extreme Yang. Thus, it consistently embodies only "blandness." (Zhang Yuansu said Poria is sweet and neutral; how can it be permeating/draining? Here, the principle of Yang absorbing Yin and Yin returning to Yang is cited to substantiate the concept of Sweet and Neutral. Then one knows Zhang Yuansu's theory is not baseless. Sweet contains the five flavors, Neutral contains the five Qi; it is the union of Yin and Yang.) Since bland originates from sweet, the True Qi containing Yin and Yang has already entered the Middle Jiao and miraculously regulated the ascent of Clear and descent of Turbid. Various Materia Medica texts claim it harmonizes the middle, benefits Qi, removes Dampness, regulates the Spleen, expels water, and calms fire. (Water and Fire are transformed from the Qi of Yin and Yang. If Clear Yang does not ascend, it stagnates and becomes Fire; if Turbid Yin does not descend, it stagnates and becomes Water. Poria has Yang Qi and Yin substance, aligning with the ascent and descent of Water and Fire. However, its taste is extremely bland, so it cannot act alone effectively.) Regulating Zang Qi and opening interstices involves directing Clear Yang Qi to the upper body from the Middle Jiao. Directing Clear Yang upward and Turbid Yin downward is also based on this principle. What deserves further investigation is that Clear and Turbid originate from Yin and Yang, and Yin and Yang manifest in Water and Fire, which are endowed by the Heart and Kidney. As Zhen Quan said, it is good at calming the Spirit, consistent with the Classic of Original Meaning's treatment of worry, resentment, fright, and palpitations. As Hao Gu said regarding securing Essence, it is close to the meaning of *Ben Cao Jing Jiu* promoting genital growth and Ri Huazi warming the waist and knees. Therefore, those using Poria should not merely adhere to the theory of bland permeation but should contemplate its fundamental mechanism of absorbing Yin from Yang and returning Yin to Yang. Regarding the claims of calming the Spirit and securing Essence, let us elaborate further.
The Heart is Yin internally and Yang externally; the Kidney is Yang internally and Yin externally. Internally lies the Spirit and the Master; externally lies Qi and Function. The Classic says: The Heart is the Great Yang within Yang. Although Poria inherits the coarse Qi of True Yang, it can absorb Yin within Yang and return it to Yang. (Yin within Yang is Blood; Blood is the spirit and Qi.) Thus, it can tonify Heart Blood. Once Yin resides within Yang, the Spirit stabilizes and Qi fills; this is also called benefiting Heart Qi. The theory of securing Essence is no different. In summary, when Yin resides within Yang in the upper part, Fire has a master and descends to interact with Water, obtaining the Fire within Water to hibernate according to Earth Qi. When Yang resides within Yin in the lower part, Water has a master and ascends to interact with Fire, obtaining the Water outside Fire to develop according to Heaven Qi. This is what is meant by Spirit being sufficient and Qi filling, Qi filling and Essence abundant, and Essence abundant and Qi secured.
It is most suitable for deficiency with Phlegm-Fire above and Damp-Heat below. If it is Yang deficiency due to overwork, with frequent urination and sweating, it is contraindicated. (Wang Haogu) *Yan Yi Bu Yi* states it is unsuitable for Yin deficiency. Those whose urination is normally smooth should avoid excessive use, as it aids dryness and damages vision. Song stated that it can be used in formulas that tonify Yin, but should not be included in drying formulas. Unlike Polyporus (Zhu Ling), which is truly bland and permeating, Poria should be avoided by those with Yin deficiency.
[Processing] Hard and white varieties are superior. Peel the skin, and it is best to wash away fibrous roots with water. If taken by mistake, it causes small black spots in the pupil and cornea of the eyes, potentially leading to blindness.