少阴一经，兼水火二气，寒热杂居，为病不可捉摸。其寒也，症类太阴；其热也，症似太阳。故仲景以微细
之病脉，欲寐之病情为提纲，立法于象外，使人求法于病中。凡症之寒热与寒热之真假，仿此义以推之，真阴之
虚实见矣。
五经提纲，皆是邪气盛则实。惟少阴提纲，是指正气夺则虚者，以少阴为人身之本也。然邪气之盛，亦因正
气之虚，故五经皆有可温可补症。正气之夺，亦由邪气之盛，故少阴亦有汗吐下者。要知邪气盛而正气已虚者，
固本即所以逐邪，正不甚虚而邪气实者，逐邪即所以护正，此大法也。少阳为阳枢，少阴为阴枢。弦为木象，弦
而细者，
是阳之少也；微为水象，微而细者，阴之少也。此脉气之相似。卫气行阳则寤，行阴则寐。其行阴二十五度，常
从足少阴之分，间行脏腑。少阴病，则枢机不利，故欲寐也。与少阳喜呕者同。呕者主出，阳主外也；寐者主入，
阴主内也。喜呕是不得呕，欲寐是不得寐，皆在病患意中，得枢机之象如此。
少阴脉微，不可发汗，亡阳故也。脉细沉数，病为在里，不可发汗，然可汗之机亦见于此。夫微为无阳，数
则有伏阳矣。须审其病为在里而禁汗，不得拘沉为在里而禁汗也。发热脉沉者，是病为在表，以无里症，故可发
汗。若脉浮而迟，表热里寒，下利清谷，是迟为无阳，病为在里，又不得拘浮为在表而发汗矣。要知阴中有阳，
沉亦可汗；阳中有阴，浮亦当温。若八九日一身手足尽热，是自里达表、阳盛阴虚，法当滋阴，又与二三日无里
症者不侔。
太阴是阳明之里，阳明不恶寒，故太阴虽吐利腹满而无恶寒症。少阴是太阳之里，太阳恶寒，故少阴吐利必
恶寒，阴从阳也。太阴手足温者，必暴烦下利而自愈，是太阴藉胃脘之阳。少阴吐利，亦必手足温者可治，手足
厥者不治，是下焦之虚寒，既侵迫于中宫，而胃脘之阳仍得敷于四末。斯知先天之元阳，仍赖后天之胃气培植也。
太阳是少阴之标，太阴是少阴之本。少阴阴虚，则移热于膀胱，故一身手足尽热而便血，从标也；少阴阳虚，
则移寒于脾土而吐利，从本也。
少阴传阳症有二∶六七日腹胀不大便者，是传阳明，脏气实则还之腑也；八九日一身手足尽热者，是传太阳，
阴出之阳，下行极而上也。
热在膀胱而便血，亦脏病传腑，此阴乘阳也，然气病而伤血，又阳乘阴也，亦见少阴中枢机之象。此是自阴
转阳，与太阳热结膀胱自下血者，见症同而病因异。
少阴病，脉紧，至七八日自下利，脉暴微，手足反温，脉紧反去者，虽烦，利必自愈。此亦是脾家实，露出
太阴底板，与太阴七八日暴烦下利自止同。盖少阴来复之阳，微则转属太阴，而秽腐自去；盛则转属阳明，而糟
粕不传。郁则内实，而入阳明大府广肠之区；横则外达，而遍太阳内外气血之部。要知紧脉转微，是复少阴本脉，
故转太阴而自解；脉沉细数，是兼阳脉，故入阳经而为患。然热虽盛不死，亦阴得阳则解之变局也。
六经皆有烦躁，而少阴更甚者，以真阴之虚也。盖阳盛则烦，阴盛则躁，烦属气，躁属形。烦发于内，躁见
于外，是形从气动也；先躁后烦，是气为形役也。不躁而时自烦，是阳和渐回，故可治；不烦而躁，是五脏之阳
已竭，惟魄独居，故死。故少阴以烦为生机，躁为死兆。
伤寒以阳为主，不特阴症见阳脉者生，亦阴病见阳症者可治也。凡 卧四逆，吐利交作，纯阴无阳之症，全
赖一阳来复，故反烦者可治，手足反温、反发热者不死耳。太阳少阴皆有身痛骨节痛之表，水气为患之里。太阳
则脉浮紧而身发热，用麻黄汤发汗，是振营卫之阳以和阴也；少阴则脉沉而手足寒，用附子汤温补，是扶坎宫之阳
以配阴也。太阳之水属上焦，小青龙汗而发之，阳水当从外散也；少阴之水属下焦，真武温而利之，阴水当从下
泄也。
阴阳俱紧，与太阳伤寒脉相似。夫紧脉为寒，当属少阴。然病发于阴，不当有汗，反汗出者，阴极似阳，阴
虚不能藏精所致也。亡阳之前，已先亡阴矣。阳无所根据，故咽痛呕吐，见虚阳之不归；阴不能藏，故下利不止，
见真阴之欲脱也。则附子汤用三白以滋阴，参、附以回阳，为少阴返本还原之剂。
肾主五液，入心为汗，少阴受病，液不上升，所以阴不得有汗。仲景治少阴之表，于麻黄细辛汤中加附子，
是升肾液而为汗也。若真阴为邪热所逼，则水随火越，故反汗出。仲景治少阴之里，附子汤中任人参，是补肾液
而止汗也。脉阴阳俱紧，口中气出条，是少阴经文，王氏集之脉法中，故诸家议论不一。夫少阴脉络肺，肺主鼻，
故鼻中涕出；少阴脉络舌本，故舌上苔滑；少阴大络注诸络以温足胫，故足冷。此症不名亡阳者，外不汗出，内
不吐利也。口中气出，唇口干躁，鼻中涕出，此为内热；阴阳脉紧，舌上苔滑， 卧足冷，又是内寒。此少阴为
枢，故见寒热相持之症，而口舌唇鼻之半表半里，恰与少阳口苦咽干目眩相应也。勿妄治者，恐阴阳相持时，清
火温补等法用之不当，宁静以待之至七日来复。微发热，手足温，是阴得阳则解也。若八日以上反大发热，再加
吐利，即是亡阳。若其人反加恶寒，是寒甚于表，上焦应之，必欲呕矣。若加腹痛是寒甚于里，中焦受之，必欲
利矣。当此阴盛，急当扶阳，庶不为假热所惑而妄治。
但欲寐，即是不得眠。然但欲寐是病情，乃问而知之；不得眠是病形，可望而知之。欲寐是阴虚，不眠是烦
躁，故治法不同。三阳惟
少阳无承气症，三阴惟少阴有承气症。少阳为阳枢，阳稍虚，便入于阴，故不得妄下，以虚其元阳。少阴为阴枢，
阳有余，便伤其阴，故当急下以存其真阴。少阳属木，惟畏其克土，故无下症；少阴主水，更畏有土制，故当急
下。盖真阴不可虚，强阳不可纵也。
少阴病用大承气急下者有三症；得病二三日，热淫于内，肾水不支，因转属阳明，胃火上炎，故口燥咽干也，
急下之，谷气下流，津液得升矣。得病六七日，当解不解，津液枯涸，因转属阳明，故腹胀不大便，所谓已入于
腑，下之则胀已，宜于急下者。六七日来，阴虚已极，恐土燥于中，心肾不交耳。若自利纯清水，心下痛，口燥
舌干者，是土燥火炎，脾气不濡，胃气反浓，水去而谷不去，故宜于急下。
少阴为性命之根，少阴病是生死关，故六经中独于少阴历言死症。然少阴中风，始得时，尚有发热脉沉可汗
症。若初受伤寒，其机甚微，脉微细但欲寐，口中和，背恶寒，人已皆不觉其为病也。若身体痛，手足寒，骨节
痛，脉沉者，此表中阳虚症；若欲吐不吐，心烦欲寐，自利而渴，小便色白者，此里之阳虚症；心烦不得卧，此
里之阴虚症也。若下利咽痛胸满心烦，与口中气出，唇口燥干，鼻中涕出， 卧足冷，舌上苔滑者，此少阴半表
半里，阴阳驳杂之症也。脉阴阳俱紧，反汗出而咽痛吐利者，此阴极似阳，肾阳不归，为亡阳症也。若至八九日，
一身手足尽热者，是寒极生热，肾阳郁极而胜复太过也。其腹痛下利，少便不利者，有水火之分；若四肢沉重疼
痛，为有水气，是阳虚而不胜阴也；若便脓血与泄利下重者，此为火郁，是阳邪陷入于阴中也。下利清谷，里寒
外热，手足厥逆，脉微欲绝，身反不恶寒，其人面赤者，是下虚而格阳也。吐利兼作，手足逆冷，烦躁欲死者，
是阴极而发躁也。岐伯曰∶“阴病治阳，阳病治阴，定其中外，各守其乡。”此即仲景治少阴之大法也。同是恶
寒卧，利止手足温者可治，利不止手足逆冷者不治。时自烦欲去衣被者可治，不烦而躁，四逆而脉不至者死。
同是吐利，手足不逆冷、反发热者不死，烦躁四逆者死。同是呕吐汗出，小便数、少者可治，自利烦躁，不得卧
者死。盖阴阳互为其根，阴中无阳则死，独阴不生故也。
少阴这一经，兼有水气和火气两种性质，寒证和热证混杂存在，致病特点难以捉摸。其表现为寒证时，症状类似太阴病；其表现为热证时，症状类似太阳病。因此，张仲景以脉象微细、精神萎靡似睡非睡（欲寐）作为少阴病的提纲，在表象之外确立治疗法则，使人从疾病的具体表现中去探求治法。凡是涉及寒热真假辨别的病症，都可以参照这一原则进行推演，从而判断真阴的虚实情况。
六经病提纲中，其余五经多指邪气盛实导致的实证。唯独少阴病的提纲，是指正气亏虚导致的虚证，因为少阴是人体生命的根本。然而，邪气的亢盛，往往是因为正气的虚弱，所以其他五经也有需要温补的证候。正气的亏损，也常由邪气的亢盛引起，所以少阴病也有适用汗法、吐法、下法的情况。必须明白：当邪气亢盛而正气已经虚弱时，固护根本就是驱逐邪气的方法；当正气尚未严重虚弱而邪气实盛时，驱逐邪气就是保护正气的方法，这是治疗的大法。少阳是阳气的枢纽，少阴是阴气的枢纽。弦脉属木之象，弦而细的脉象，表示阳气不足；微脉属水之象，微而细的脉象，表示阴气不足。这是脉气的相似之处。卫气行于阳分则人清醒，行于阴分则人入睡。卫气行于阴分二十五周次，通常从足少阴肾经的分野开始，穿插运行于脏腑之间。患少阴病时，枢机运转不利，所以出现想睡觉的症状。这与少阳病喜欢呕吐的道理相同。呕吐主外出，属阳，主外；睡眠主内入，属阴，主内。喜欢呕吐其实是“想呕却呕不出来”，想睡觉其实是“想睡却睡不着”，这些都发生在患者的意识之中，体现了枢机运行的这种象意。
少阴病脉象微弱，不可使用发汗法，因为会导致亡阳。如果脉象细沉数，说明病位在里，不可发汗，但发汗的机理也可能隐含其中。微脉代表无阳，数脉则代表有伏藏的阳气。必须仔细审查病情是否在里从而禁止发汗，不能仅仅因为脉沉就认为病在里而禁止发汗。如果发热且脉沉，说明病在表，因为没有里证，所以可以发汗。如果脉浮而迟，表现为表热里寒，伴有腹泻完谷不化，迟脉代表无阳，病在里，此时又不能仅仅因为脉浮就认为病在表而发汗了。要明白阴中有阳，沉脉也可以发汗；阳中有阴，浮脉也应当温补。如果是患病八九天后，全身和手足都发热，这是病邪从里达表、阳气盛而阴虚的表现，治法应当滋阴，这与患病二三日没有里证的情况不同。
太阴是阳明的里层，阳明不怕冷，所以太阴即使有呕吐、腹泻、腹部胀满等症状，也没有怕冷的表现。少阴是太阳的里层，太阳怕冷，所以少阴出现呕吐、腹泻时必定怕冷，这是因为阴随阳的缘故。太阴病如果手足温暖，必定会出现突然烦躁并腹泻，随后自愈，这是因为太阴借助了胃脘的阳气。少阴病出现呕吐、腹泻时，如果手足温暖则是可治之症，如果手足厥冷则是难治之症，这说明下焦的虚寒虽然已经侵迫到中焦脾胃，但胃脘的阳气仍然能够布散到四肢末端。由此可知，先天的元阳，仍然依赖后天的胃气来培植。
太阳是少阴的标象，太阴是少阴的本源。少阴阴虚，则热邪移注于膀胱，导致全身和手足发热以及便血，这是从标论治；少阴阳虚，则寒邪移注于脾土导致呕吐腹泻，这是从本论治。
少阴病传变为阳证有两种情况：患病六七日后出现腹胀不大便，这是传变至阳明，脏气实转而归于腑；患病八九天全身和手足都发热，这是传变至太阳，阴气出于阳位，下行至极点而向上反弹。
热邪在膀胱导致便血，也是脏病传腑，这是阴乘阳位，但气病伤血，又是阳乘阴位，这也体现了少阴中枢枢机的象意。这是自阴转阳，与太阳病热结膀胱导致自行下血的病症，症状相同但病因不同。
少阴病，脉紧，到了七八日自行腹泻，脉象突然变得微弱，手足反而温暖，脉紧反而消失，虽然感到烦闷，但腹泻必定会自愈。这也是脾家实（脾气恢复），显露出太阴的底面，与太阴病七八日突然烦躁腹泻后自愈的情况相同。大概少阴来复的阳气，微弱则转属于太阴，体内的秽浊腐物自然排出；旺盛则转属于阳明，糟粕得以传导。郁结则形成内实，进入阳明大肠的区域；横溢则向外通达，遍布太阳内外气血的部位。要明白紧脉转为微脉，是恢复了少阴的本脉，所以转属太阴而自愈；如果脉象沉细数，是兼有阳脉，所以进入阳经而成为病患。然而热势虽盛也不会死亡，这也是阴得阳助而解的一种变局。
六经病都有烦躁，但少阴病更为严重，这是因为真阴亏虚的缘故。大概阳气盛则烦，阴气盛则躁，烦属于气分，躁属于形质。烦发作于体内，躁显现于体表，这是形质随气动荡；先躁后烦，是气被形质所役使。不躁而时常自烦，说明阳气逐渐回复，所以可治；不烦而躁，说明五脏的阳气已经竭尽，只有魄独居，所以致死。因此，少阴病以烦为生机，以躁为死兆。
伤寒病以阳气为主，不仅阴证见到阳脉者生，而且阴病出现阳证症状者也可治。凡是四肢厥逆、呕吐腹泻交作、纯阴无阳的病症，全赖一阳来复，所以如果出现反烦的症状则可治，如果手足反温、反发热则不死。太阳病和少阴病都有身痛骨节痛的表证，以及水气为患的里证。太阳病则脉浮紧且身体发热，用麻黄汤发汗，这是振奋营卫的阳气以调和阴气；少阴病则脉沉且手足寒冷，用附子汤温补，这是扶持坎宫（肾）的阳气以配合阴气。太阳的水气属于上焦，用小青龙汤发汗发散，阳水应当从外表消散；少阴的水气属于下焦，用真武汤温阳利水，阴水应当从下面排泄。
阴阳俱紧的脉象，与太阳伤寒的脉象相似。紧脉主寒，应当属于少阴。然而病发于阴，不应当有汗，反而出汗的，是阴极似阳，阴虚不能藏精所致。在亡阳之前，已经先发生了亡阴。阳气无所依附，所以出现咽痛呕吐，显示出虚阳不归位；阴气不能固藏，所以出现腹泻不止，显示出真阴欲脱。因此，附子汤使用三白（茯苓、芍药、白术）以滋阴，人参、附子以回阳，是少阴病返本还原的方剂。
肾主管五液，入心则为汗，少阴受病，津液不能上升，所以阴证不应该有汗。张仲景治疗少阴的表证，在麻黄细辛附子汤中加入附子，是提升肾液化为汗。如果真阴被邪热逼迫，则水随火势上越，所以反而出汗。张仲景治疗少阴的里证，在附子汤中重用参，是补肾液以止汗。脉象阴阳俱紧，口中气息粗大，这是少阴经文的内容，王叔和将其收录在脉法中，所以各家议论不一。少阴脉络通肺，肺主鼻，所以鼻涕流出；少阴脉络连系舌根，所以舌苔滑润；少阴的大络注入各络脉以温暖足胫，所以脚冷。此症不命名为亡阳，是因为外部不出汗，内部不呕吐腹泻。口中气息粗大，嘴唇口干，鼻涕流出，这是内热；阴阳脉紧，舌苔滑润，躺卧时脚冷，这又是内寒。这是少阴作为枢纽，所以出现寒热相持的症状，而口、舌、唇、鼻处于半表半里，恰好与少阳病的口苦、咽干、目眩相应。不要胡乱治疗，恐怕在阴阳相持之时，清热泻火或温补等用法不当，应宁静等待，直到第七天阳气来复。轻微发热，手足温暖，是阴得阳助而解。如果八日以上反而大发高热，再加上呕吐腹泻，就是亡阳。如果病人反而加重怕冷，是寒邪甚于表，上焦感应到，必定想要呕吐。如果加上腹痛，是寒邪甚于里，中焦受到侵害，必定想要腹泻。当此阴气极盛之时，应当紧急扶助阳气，以免被假热迷惑而胡乱治疗。
只想睡觉，就是不得安眠。然而“但欲寐”是病情的描述，是通过询问得知的；“不得眠”是病形的表现，是通过观察得知的。想睡觉是阴虚，不睡觉是烦躁，所以治疗方法不同。三阳病中只有少阳没有承气汤证，三阴病中只有少阴有承气汤证。少阳是阳的枢纽，阳气稍虚就会陷入阴分，所以不能妄用下法，以免损伤元阳。少阴是阴的枢纽，阳气有余就会伤害阴液，所以应当紧急攻下以保存真阴。少阳属木，只害怕克制脾土，所以没有下法适应证；少阴主水，更害怕被土所制，所以应当紧急攻下。大概真阴不可使其虚弱，强阳不可放纵。
少阴病使用大承气汤急下的有三种情况：患病两三天，热邪淫溢于内，肾水支撑不住，因而转属阳明，胃火上炎，所以口燥咽干，应当急下，使谷气下行，津液得以升腾。患病六七天，应当解除病邪而未解除，津液枯涸，因而转属阳明，所以腹胀不大便，所谓病邪已入于腑，攻下则胀满消除，适宜急下的是这种情况。患病六七天，阴虚已到极点，恐怕中焦土燥，导致心肾不交。如果自行腹泻纯清水，心下疼痛，口燥舌干，这是土燥火炎，脾气不濡润，胃气反而浓浊，水去而谷不去，所以适宜急下。
少阴是性命的根本，少阴病是生死的关口，所以在六经病中唯独对少阴详细论述了死证。然而少阴中风，初起时，还有发热、脉沉可发汗的证候。如果起初感受伤寒，其病机很细微，脉微细只想睡觉，口中平和，背部怕冷，人们都已经不觉得这是病了。如果身体疼痛，手足寒冷，骨节疼痛，脉沉，这是表阳虚的证候；如果想吐又吐不出来，心烦想睡觉，自行腹泻且口渴，小便颜色白，这是里阳虚的证候；心烦不得卧，这是里阴虚的证候。如果腹泻、咽痛、胸满、心烦，以及口中气息粗大，嘴唇口干，鼻涕流出，躺卧脚冷，舌苔滑润，这是少阴半表半里，阴阳混杂的证候。脉象阴阳俱紧，反而出汗且咽痛腹泻，这是阴极似阳，肾阳不归位，属于亡阳证。如果到了八九天，全身和手足都发热，这是寒极生热，肾阳郁积至极而胜复太过。如果有腹痛腹泻，小便不利，是有水火的分别；如果四肢沉重疼痛，是有水气，这是阳虚不能胜过阴邪。如果大便脓血和泄利下重，这是火郁，是阳邪陷入阴中。腹泻完谷不化，里寒外热，手足厥冷，脉微欲绝，身体反而不怕冷，面色发红，这是下虚格阳。呕吐腹泻并作，手足逆冷，烦躁欲死，这是阴极而发躁。岐伯说：“阴病治阳，阳病治阴，定其中外，各守其乡。”这就是张仲景治疗少阴的大法。同样是恶寒想睡，腹泻停止手足温暖的可以治，腹泻不止手足逆冷的不治。时常自烦想去掉衣被的可以治，不烦而躁，四肢厥逆且脉搏摸不到的死。同样是呕吐腹泻，手足不逆冷反而发热的不死，烦躁四肢逆冷的死。同样是呕吐出汗，小便频数或少量的可治，自行腹泻烦躁不得卧的死。大概阴阳互为根本，阴中没有阳则死，独阴不能生长。
Shaoyin (Lesser Yin) channel involves both Water and Fire Qi. Cold and Heat syndromes coexist, making the pathology unpredictable. When manifesting as cold, symptoms resemble Taiyin (Greater Yin) disease; when manifesting as heat, symptoms resemble Taiyang (Greater Yang) disease. Therefore, Zhang Zhongjing established the diagnostic criteria using the pulse of "microfine" (Wei Xi, 微细) and the mental state of "desire to sleep but unable to do so properly" (Yu Mei, 欲寐). He formulated laws beyond mere appearance, guiding practitioners to seek treatment principles within the specific manifestations of the disease. By applying this logic to differentiate true and false cold/heat patterns, one can determine the deficiency or excess of True Yin.
The diagnostic criteria for the other five channels generally indicate excess caused by pathogenic factors. Only the Shaoyin criterion indicates deficiency caused by the depletion of healthy Qi (Zheng Qi, 正气), because Shaoyin is the root of human life. However, excessive pathogenic factors often arise from deficient healthy Qi, hence all five channels may have indications for warming and tonifying. Conversely, depletion of healthy Qi is often due to excessive pathogenic factors, so Shaoyin disease may also present indications for sweating, vomiting, or purging methods. It must be understood that when pathogens are excessive and healthy Qi is already deficient, consolidating the root is equivalent to expelling pathogens. When healthy Qi is not severely deficient but pathogens are substantial, expelling pathogens is equivalent to protecting healthy Qi. This is a fundamental principle. Shaoyang (Lesser Yang) is the pivot of Yang; Shaoyin is the pivot of Yin. The Xian (Wiry) pulse represents Wood; a wiry and fine pulse indicates insufficient Yang. The Wei (Faint) pulse represents Water; a faint and fine pulse indicates insufficient Yin. These are similarities in pulse energy. Wei Qi (Defensive Qi) circulates in Yang leading to wakefulness, and in Yin leading to sleep. Its circulation in Yin occurs twenty-five cycles, usually starting from the distribution area of Foot Shaoyin, interweaving through the Zang-Fu organs. In Shaoyin disease, the pivot mechanism fails, resulting in the desire to sleep. This parallels the frequent retching seen in Shaoyang disease. Retching implies expulsion, associated with Yang and exterior; sleep implies entry, associated with Yin and interior. "Frequent retching" actually means "unable to vomit freely," and "desire to sleep" means "unable to sleep soundly." Both occur within the patient's consciousness, reflecting the imagery of the pivot mechanism.
In Shaoyin disease, if the pulse is faint, sweating should not be induced, as it would lead to the collapse of Yang. If the pulse is fine, deep, and rapid, the disease is in the interior, and sweating is contraindicated; however, the potential for sweating may still be discerned. A faint pulse indicates absence of Yang, while a rapid pulse suggests hidden Yang. One must carefully examine whether the disease is in the interior to prohibit sweating, rather than simply prohibiting sweating because the pulse is deep. If there is fever with a deep pulse, the disease is considered in the exterior (due to lack of interior signs), and sweating may be induced. If the pulse is floating and slow, indicating exterior heat and interior cold with diarrhea of undigested food, the slow pulse indicates absence of Yang and interior disease; thus, one cannot induce sweating merely because the pulse is floating. One must understand that Yang exists within Yin, so even a deep pulse may allow for sweating; Yin exists within Yang, so even a floating pulse may require warming. If after eight or nine days, the whole body and extremities become hot, it indicates pathogen moving from interior to exterior, with Yang excess and Yin deficiency. The treatment should be to nourish Yin, which differs from cases on day two or three without interior signs.
Taiyin is the interior of Yangming. Since Yangming does not fear cold, Taiyin, despite having vomiting, diarrhea, and abdominal fullness, does not present aversion to cold. Shaoyin is the interior of Taiyang. Since Taiyang fears cold, Shaoyin, when presenting vomiting and diarrhea, must present aversion to cold, as Yin follows Yang. In Taiyin, if hands and feet are warm, sudden irritability followed by diarrhea leads to self-healing, relying on the Yang of the stomach. In Shaoyin, if vomiting and diarrhea occur but hands and feet remain warm, it is treatable; if hands and feet are cold, it is untreatable. This shows that although lower Jiao deficiency-cold invades the central palace (Spleen/Stomach), the Yang of the stomach still reaches the four extremities. Thus,先天 Yuan Yang (Primordial Yang) relies on postnatal Stomach Qi for cultivation.
Taiyang is the mark (Biao, 标) of Shaoyin; Taiyin is the root (Ben, 本) of Shaoyin. If Shaoyin Yin is deficient, heat transfers to the Bladder, causing whole-body and extremity heat and blood in stool, following the Mark. If Shaoyin Yang is deficient, cold transfers to Spleen Earth, causing vomiting and diarrhea, following the Root.
There are two types of Shaoyin transmitting to Yang syndromes: Abdominal distension and constipation after six or seven days indicates transmission to Yangming, where Zang excess returns to the Fu organs. Whole-body and extremity heat after eight or nine days indicates transmission to Taiyang, where Yin emerges into Yang, rising after reaching the extreme downward position.
Heat in the Bladder causing blood in stool is also Zang-to-Fu transmission, representing Yin invading Yang. However, Qi pathology injuring Blood represents Yang invading Yin. This also reflects the pivot imagery of Shaoyin. This is a transition from Yin to Yang, differing from Taiyang heat binding in the Bladder causing spontaneous bleeding, though symptoms are similar, etiologies differ.
In Shaoyin disease, if the pulse is tight, and after seven or eight days spontaneous diarrhea occurs, with the pulse suddenly becoming faint, hands and feet turning warm, and the tightness disappearing, despite irritability, the diarrhea will likely stop spontaneously. This is akin to "Splei Home Excess" revealing the Taiyin foundation, similar to Taiyin's spontaneous resolution after sudden irritability and diarrhea on day seven or eight. Generally, the recovering Yang of Shaoyin, if weak, shifts to Taiyin, clearing turbidity; if strong, shifts to Yangming, facilitating waste passage. Stagnation leads to interior excess entering Yangming's large intestine; horizontal spread reaches Taiyang's Qi and Blood regions. Note that tight pulse turning faint restores the original Shaoyin pulse, leading to resolution via Taiyin. Deep, fine, rapid pulses indicate concurrent Yang involvement, leading to illness in Yang channels. Although heat may be severe, death does not ensue; this is a variation of Yin resolving with Yang support.
Irritability (Fan, 烦) and restlessness (Zao, 躁) occur in all six channels, but are more severe in Shaoyin due to True Yin deficiency. Yang excess causes Fan; Yin excess causes Zao. Fan belongs to Qi; Zao belongs to Form. Fan arises internally; Zao manifests externally, meaning Form follows Qi movement. If Zao precedes Fan, Qi is enslaved by Form. Without Zao but with occasional Fan, Yang harmony gradually returns, indicating treatability. Without Fan but with Zao, Zang-Fu Yang is exhausted, leaving only Po (Corporeal Soul), indicating death. Thus, in Shaoyin, Fan signifies vitality, while Zao signifies mortality.
Shanghan (Cold Damage) prioritizes Yang. Not only do Yin syndromes with Yang pulses indicate survival, but Yin diseases with Yang symptoms are also treatable. For conditions like Si Ni (Four Extremities Cold), alternating vomiting and diarrhea, representing pure Yin without Yang, recovery depends on the return of one Yang. Hence, counter-irritability is treatable; counter-warmth or counter-fever in extremities indicates non-lethality. Both Taiyang and Shaoyin present exterior body/bone joint pain and interior water-Qi pathology. Taiyang presents floating-tight pulse and fever, treated with Mahuang Tang (Ephedra Decoction) to sweat,振 Ying Wei Yang (Stimulating Defensive-Nutritive Yang) to harmonize Yin. Shaoyin presents deep pulse and cold extremities, treated with Fuzi Tang (Aconite Decoction) to warm and tonify, supporting Kan Palace (Kidney) Yang to match Yin. Taiyang water belongs to Upper Jiao, treated with Xiao Qinglong Tang (Minor Blue Dragon Decoction) to sweat and disperse, dispersing Yang water externally. Shaoyin water belongs to Lower Jiao, treated with Zhen Wu Tang (True Warrior Decoction) to warm and drain, excreting Yin water downwards.
Yin-Yang both tight pulses resemble Taiyang Shanghan. Tight pulse indicates cold, belonging to Shaoyin. Disease originating in Yin should not sweat; if sweating occurs, it is extreme Yin resembling Yang, caused by Yin deficiency failing to store Essence. Before Yang collapse, Yin collapse has already occurred. With no basis for Yang, throat pain and vomiting appear, showing unrooted deficient Yang. With inability to store Yin, continuous diarrhea appears, showing impending loss of True Yin. Therefore, Fuzi Tang uses San Bai (Poria, Peony, Atractylodes) to nourish Yin, and Ren Shen (Ginseng) plus Fu Zi (Aconite) to restore Yang, serving as a formula for Shaoyin to return to its origin.
Kidney governs five fluids; entering Heart, it becomes sweat. In Shaoyin disease, fluids do not ascend, so Yin syndromes should not sweat. Zhang Zhongjing treats Shaoyin exterior syndrome by adding Fu Zi to Mahuang Xixin Tang (Ephedra and Asarum Decoction), raising Kidney fluid to form sweat. If True Yin is forced by pathogenic heat, water follows fire upward, causing spontaneous sweating. Zhang Zhongjing treats Shaoyin interior syndrome by employing Ren Shen in Fuzi Tang, tonifying Kidney fluid to stop sweating. "Yin-Yang both tight, breath issuing from mouth" is Shaoyin text collected by Wang Shuhe in Pulse Methods, causing varied interpretations. Shaoyin meridians connect to Lung; Lung governs nose, hence nasal discharge. Shaoyin meridians connect to tongue base, hence slippery tongue coating. Shaoyin major collaterals warm calves, hence cold feet. This syndrome is not named Yang Collapse because there is no external sweating or internal vomiting/diarrhea. Breath issue, dry lips/mouth, nasal discharge indicate interior heat. Yin-Yang tight pulse, slippery coating, cold feet lying down indicate interior cold. As Shaoyin is the pivot, cold and heat contend. The semi-exterior/semi-interior nature of mouth, tongue, lips, and nose corresponds to Shaoyang's bitter taste, dry throat, and vertigo. Do not treat rashly; during Yin-Yang contention, improper use of cooling or warming may fail. Wait quietly until day seven for Yang recovery. Mild fever and warm extremities indicate Yin resolving with Yang. If after eight days high fever worsens with vomiting/diarrhea, it is Yang Collapse. If aversion to cold worsens, cold is severe in exterior, affecting Upper Jiao, leading to vomiting. If abdominal pain adds, cold is severe in interior, affecting Middle Jiao, leading to diarrhea. In this state of Yin excess, urgently support Yang to avoid being misled by false heat.
"Desire to sleep" (Dan Yu Mei, 但欲寐) equates to insomnia. "Desire to sleep" describes the condition, known via inquiry; "insomnia" describes the form, known via observation. Desire to sleep indicates Yin deficiency; insomnia indicates irritability. Treatments differ. Among Three Yang channels, only Shaoyang lacks Chengqi (Purgative) indications. Among Three Yin channels, only Shaoyin has Chengqi indications. Shaoyang is Yang pivot; slight Yang deficiency enters Yin, so purging is forbidden to protect Yuan Yang. Shaoyin is Yin pivot; Yang excess injures Yin, so urgent purging is required to preserve True Yin. Shaoyang belongs to Wood, fearing Earth suppression, so no purging indications. Shaoyin governs Water, fearing Earth control, so urgent purging is needed. True Yin must not be deficient; Strong Yang must not be indulged.
There are three indications for urgent purging with Dachengqi Tang (Major Order the Qi Decoction) in Shaoyin disease:
1. Onset 2-3 days: Heat rampant inside, Kidney Water unable to support, transferring to Yangming, Stomach Fire flaring up, causing dry mouth/throat. Urgent purging allows Grain Qi to flow down and Fluids to rise.
2. Onset 6-7 days: Failure to resolve, fluids dried up, transferring to Yangming, causing abdominal distension and constipation. Pathogen entered Fu organ; purging resolves distension. Urgent purging is indicated. Yin deficiency is extreme; fear of Dry Earth in middle preventing Heart-Kidney intersection.
3. Spontaneous diarrhea of clear water, epigastric pain, dry mouth/tongue: Dry Earth and flaming Fire, Spleen Qi not moistening, Stomach Qi thickening. Water gone, grain remains. Urgent purging is indicated.
Shaoyin is the root of life and death. Thus, among Six Channels, only Shaoyin details fatal syndromes. However, early Shaoyin Wind Strike may still show fever and deep pulse, allowing sweating. Early Cold Damage presents subtle mechanism: microfine pulse, desire to sleep, neutral mouth, back aversion to cold; patients may not recognize it as disease. Body pain, cold extremities, bone/joint pain, deep pulse indicate Exterior Yang deficiency. Wanting to vomit without doing so, irritability, desire to sleep, spontaneous diarrhea with thirst, white urine indicate Interior Yang deficiency. Irritability preventing sleep indicates Interior Yin deficiency. Diarrhea, sore throat, chest fullness, irritability, breath issue, dry lips, nasal discharge, cold feet, slippery coating indicate Shaoyin semi-exterior/semi-interior mixed Yin-Yang syndrome. Yin-Yang tight pulse with spontaneous sweating, sore throat, vomiting/diarrhea indicates Extreme Yin resembling Yang, Kidney Yang unrooted, Yang Collapse syndrome. Day 8-9 whole-body/extremity heat indicates Cold extreme generating Heat, Kidney Yang郁积 (stagnant) and rebounding excessively. Abdominal pain, diarrhea, difficult urination indicate Water/Fire distinction. Heavy/painful limbs indicate Water Qi, Yang deficiency unable to overcome Yin. Pus/blood in stool and heavy tenesmus indicate Fire stagnation, Yang pathogen sinking into Yin. Diarrhea of undigested food, interior cold/exterior heat, cold extremities, faint pulse, body not averse to cold, red face indicate Lower deficiency repelling Yang. Vomiting/diarrhea with cold extremities and severe irritability indicate Extreme Yin triggering agitation. Qibo said: "Treat Yang for Yin disease, Yin for Yang disease; stabilize center and periphery, each guard its place." This is Zhang Zhongjing's great method for Shaoyin. Same aversion to sleep: diarrhea stopping with warm extremities is treatable; diarrhea continuing with cold extremities is untreatable. Occasional irritability wanting to remove clothes is treatable; no irritability but restlessness, cold extremities, absent pulse is fatal. Same vomiting/diarrhea: extremities not cold, counter-fever is non-fatal; irritability with cold extremities is fatal. Same vomiting/sweating, frequent/scanty urine is treatable; spontaneous diarrhea with irritability and inability to lie down is fatal. Yin and Yang are mutual roots; Yin without Yang dies; solitary Yin cannot generate.