古称乙癸同源，肝肾同治，其说维何？盖火分君相，君火居乎上而主静，相火处乎下而主动。君火唯一，心
主是也。相火有二，乃肾乃肝。肾应北方壬癸，于卦为坎，于象为龙，龙潜海底，龙起而火随之。肝应东方甲乙，
于卦为震，于象为雷，雷藏泽中，雷起而火随之。泽也海也，无非水也，无非下也，故曰乙癸同源。东方者，天
地之春也，勾萌甲拆，气满乾坤。在人为怒，怒则气上而居七情之升。在天为风，风则气鼓而为百病之长。怒而
补之，将逆而郁结。风而补之，将暴而摧折矣。北方者，天地之冬也，草木黄落、六宇萧条。在人为恐，恐则气
下而居七情之降。在天为寒，寒则气惨而应万象之衰。恐而泄之，将悚而颠扑。寒而泻之，将敛而战栗矣。所谓
东方之木，非虚勿补，补肾即所以补肝。北方之水无实毋泻，泻肝乃所以泻肾，中有至理也，
故曰肝肾同治。虽然木既常实耳，水既常虚耳，又言补肝泻肾者何哉？盖邪不可亢，亢则害正，泻之犹补之也。
正宜长固，固则御邪，补之犹泻之也。若夫血不足者濡之，水之属也，滋水之源，木赖以荣。气有余者泄之，木
之属也，伐木之干，水用而充，则又是肝肾同治矣。少火生气，气有余便火。壮火食气，气不足便是寒。泻木所
以抑气，补水所以制火，气即火，火即气，则又是乙癸同源矣。是为说。
古人称“乙癸同源，肝肾同治”，这种说法的依据是什么呢？大概是因为火分为君火和相火。君火位于上部而主静，相火位于下部而主动。君火只有一，即心主（心脏）。相火有两，分别是肾和肝。肾对应北方的壬癸水，在八卦中属于坎卦，在物象上象征龙，龙潜藏于海底，龙兴起时火随之而起。肝对应东方的甲乙木，在八卦中属于震卦，在物象上象征雷，雷隐藏于沼泽之中，雷兴起时火随之而起。沼泽和大海，无非都是水，无非都在下方，所以说乙癸同源。东方，是天地间的春季，草木萌芽破壳，气充满乾坤。在人体表现为怒，怒则气机上逆，居于七情中的上升类。在天象表现为风，风则鼓动气机，成为百病之长。对怒气进行补益，将会导致气机逆乱而郁结。对风邪进行补益，将会导致病情暴烈而摧折身体。北方，是天地间的冬季，草木枯黄凋落，宇宙萧条冷清。在人体表现为恐，恐则气机下沉，居于七情中的下降类。在天象表现为寒，寒则气机惨烈，应合万物的衰败。对恐惧进行泄法，将会导致惊惧而跌倒扑伤。对寒气进行泻法，将会导致收敛而战栗发抖。所谓东方的木，不虚不补，补肾就是用来补肝的方法。北方的水无实勿泻，泻肝就是用来泻肾的方法，这其中蕴含着深刻的道理，所以说是肝肾同治。虽然木常常偏实，水常常偏虚，为什么又说要补肝泻肾呢？大概是因为邪气不可亢盛，亢盛就会伤害正气，泻邪气犹如同补益正气一样。正气应当长久固守，固守则能抵御邪气，补益正气犹如同泻除邪气一样。至于血不足的，用濡润之法，这属于水的范畴，滋补水之源，树木依靠它而繁荣。气有余的，用泄法，这属于木的范畴，砍伐树木的主干，水得以充盈，这又是肝肾同治了。少火（生理之火）生气，气有余便化为火。壮火（病理之火）食气，气不足便是寒。泻肝木是为了抑制气机，补肾水是为了制约火，气即是火，火即是气，这又是乙癸同源的道理了。这就是所说的理论。
The ancients stated that "Yi and Gui share the same source, and the Liver and Kidney are treated together." What is the basis for this theory? It is because Fire is divided into Ministerial Fire (Jun Huo) and Ministerial Fire (Xiang Huo). Ministerial Fire resides in the upper part and governs stillness, while Ministerial Fire resides in the lower part and governs movement. There is only one Ministerial Fire, which is the Heart Master (Zang Zhu). There are two Ministerial Fires, namely the Kidney and the Liver. The Kidney corresponds to Ren and Gui of the North, belongs to the Kan trigram in the Eight Trigrams, and symbolizes the Dragon in imagery. When the Dragon hides at the bottom of the sea, its rising brings fire with it. The Liver corresponds to Jia and Yi of the East, belongs to the Zhen trigram, and symbolizes Thunder in imagery. When Thunder hides in the marsh, its rising brings fire with it. Marshes and seas are nothing but water, and nothing but below; thus, it is said that Yi and Gui share the same source. The East represents Spring in Heaven and Earth, where buds sprout and shells split, and Qi fills the universe. In humans, it manifests as Anger (Nu); anger causes Qi to ascend, belonging to the ascending category among the Seven Emotions. In nature, it manifests as Wind (Feng); wind agitates Qi and becomes the chief of all diseases. Tonifying anger will cause Qi to rebel and stagnate. Tonifying wind will cause violent destruction. The North represents Winter in Heaven and Earth, where grass and trees wither and fall, and the universe is desolate. In humans, it manifests as Fear (Kong); fear causes Qi to descend, belonging to the descending category among the Seven Emotions. In nature, it manifests as Cold (Han); cold makes Qi bleak and corresponds to the decline of all phenomena. Draining fear will cause fright and falling. Purging cold will cause contraction and shivering. Therefore, regarding the Wood of the East, do not tonify if there is no deficiency; tonifying the Kidney is the method to tonify the Liver. Regarding the Water of the North, do not drain if there is no excess; draining the Liver is the method to drain the Kidney. This contains profound principles, hence it is said that the Liver and Kidney are treated together. Although Wood is often excessive and Water is often deficient, why speak of tonifying the Liver and draining the Kidney? Generally, pathogenic factors should not be allowed to become hyperactive; hyperactivity harms righteous Qi, so draining them is akin to tonifying. Righteous Qi should be firmly consolidated; consolidation resists pathogens, so tonifying is akin to draining. As for insufficiency of Blood, moisten it; this belongs to the category of Water. Nourishing the source of Water allows Wood to flourish. For excess of Qi, drain it; this belongs to the category of Wood. Pruning the trunk of Wood allows Water to fill up; this is again the treatment of the Liver and Kidney together. Mild Fire generates Qi; excess Qi transforms into Fire. Vigorous Fire consumes Qi; insufficiency of Qi results in Cold. Draining Liver Wood suppresses Qi; tonifying Kidney Water controls Fire. Since Qi is Fire and Fire is Qi, this illustrates that Yi and Gui share the same source. This is the explanation.