【纲】仲景曰。少阴之为病。脉微细。但欲寐也。
【目】方中行曰。脉沉细者。少阴居于极下。起于小指之下也。针经曰。是主肾所生病者。嗜
寐。盖人肖天地。天地之气。行于阳。则辟而晓。行于阴。则阖而晦。故人之气。行于阳。则动而
寤。行于阴。则静而寐。然则但欲寐者。邪客于阴也。
魏荔彤曰。伤寒三阳。递传三阴。复自太阴传少阴。此传经之邪。乃外感风寒。历久变热之热
邪也。亦有直中少阴经脏者。又非传经热邪可比。乃阴寒之寒邪也。故三阳分经与腑。三阴分经与
脏。如少阴病。其为传经热邪。直中寒邪。当辨也。若此条。则合传经直中二邪而总标其脉症也。
少阴为病。脉必沉。三阴皆然。又兼微细。异乎三阳之浮大弦也。沉对浮。微对大。细对弦。此少
阴脉也。见此则三阴俱可识其端倪。至少阴为症。有寒热二邪。本不尽同。姑取两邪入而见症大同
者。则但欲寐也。肾司智巧。热邪入而扰其阴。寒邪入而溷其阳。因致 欲寐。仲师示人未辨寒
热之邪。先辨少阴之症。此至诀也。脉之沉微细。三阴俱有。兼以但欲寐。则少阴病也。但沉微细。
虽三阴皆有。而太阴必多微。少阴必多沉。厥阴必多细。太阴在中。故微多。少阴在下。故沉多。
厥阴近胆。故弦可变细而细多。盖细即弦之微者。此仲师于少阴。不言沉。反言微细者。沉少阴本脉。不须言。且沉亦
非少阴独有之脉。必兼太
阴之微。厥阴之细。而少阴之脉始确也。再者。少阴处三阴之中。亦如阳明处三阳之中。阳明之脉
本大。然兼太阳之浮多。则太阳阳明也。兼少阳之弦多。则少阳阳明也。推之三阴。少阴之为脉。
何独不然乎。然则少阴之沉。兼微多。非太阴之少阴乎。少阴之沉兼细多。非厥阴之少阴乎。三阳
之阳明。由递传而言之。有相通之义。仲师故分而为三。三阴之少阴。亦就递传而言之。有相通之
义。何不可引而伸之哉。
【纲】仲景曰。少阴病。欲吐不吐。心烦。但欲寐。五六日。自利而渴者。属少阴也。虚故引
水自救。若小便色白者。少阴病形悉具。小便白者。以下焦虚。有寒。不能制水。故令色白也。
【目】王肯堂曰。少阴病。如本条诸症。理中四逆辈。阴症虽云不用麻黄。如少阴始得病。反
发热。脉沉者。麻黄附子细辛汤。于六经但少阴症难辨。本经但云脉微细欲寐。小便数而白。背恶
寒。四肢厥者。可不审而知之。或虽有恶寒甚者。不觉寒。但喜浓。衣近火也。其脉微细。或沉涩。
虽有阴阳俱紧者。盖其人素有热。为表寒外袭。故如此。但当察其外症为主。必以温药逐之。其
阳邪传入。与少阴自受热症。宜下宜吐宜和者多矣。仲景虽不言滑实沉数诸可下之脉。然与症则可知
矣。脉必相符也。虽或有反沉微细迟。脉不应症者。为不可下。亦宜凉剂滋阴退阳而愈。不愈。必
待脉有力而后下之可也。其有症恶寒。急下之者。倘反有脉不应病。亦宜微下之。虽不敢大下。亦
不可缓也。六经惟少阴传变。与太阳相同。如真武汤、四逆汤通脉四逆汤症。俱有加减法。谓有或
为之症。亦犹小青龙小柴胡是也。
【纲】仲景曰。脉阴阳俱紧者。口中气出。唇口燥干。鼻中涕出。蜷卧。足冷。舌上胎滑。勿
妄治也。少阴病。下利。若利自止。恶寒而蜷卧。手足温者。可治。少阴病。恶寒。身蜷而利。手
足逆冷者。不治。
【目】鳌按。首条蜷卧。由于内寒。二三条亦同一蜷卧。却以手足温手足逆冷为凭。见可治不
可治之故。盖温者。阳回也。逆冷者。纯阴无阳也。
【纲】仲景曰。少阴病。脉沉微细。但欲寐。汗出不烦。自欲吐。至五六日。自利。复烦躁。
不得卧寐者死。
【目】陶华曰。阳气虚。阴气盛。则目瞑。故多寐。乃邪气传于阴而不在阳也。昏昏闭目者。
阴自阖也。默默不言者。阴主静也。阳气盛。阴气虚。则昼夜不得眠。盖夜以阴为主。阴气盛则目
闭不安卧。若阴为阳所胜。故终夜烦扰而不得眠。所谓阴虚则夜争者是也。
鳌按。始而欲寐。是少阴本症。五六日后不得卧寐。是微阳欲绝也。其何能生。
【纲】张仲景说：少阴病的特征，是脉象微细，精神萎靡只想睡觉。
【目】方中行说：脉象沉细，是因为少阴经位于人体最下部，起于足小趾之下。《针经》说：少阴经主治肾脏所生的疾病，症状包括嗜睡。大概人效法天地，天地之气运行于阳分，则开启而明亮；运行于阴分，则闭合而昏暗。所以人的气运行于阳分，则活动而清醒；运行于阴分，则安静而睡眠。那么，“但欲寐”（只想睡觉），就是邪气客居在阴分所致。
魏荔彤说：伤寒病从三阳经依次传入三阴经，又由太阴经传入少阴经。这种传经的邪气，是外感风寒，经过长时间变化而成的热邪。也有直接中伤少阴经和脏腑的，这又不是传经热邪所能比拟的，属于阴寒之邪。所以三阳经分为经证与腑证，三阴经分为经证与脏证。例如少阴病，需要辨别它是传经的热邪，还是直中的寒邪。像这一条经文，则是将传经和直中两种邪气综合起来，总括标示其脉象和症状。患少阴病，脉象必定沉。三阴病都是如此，又兼见微细，这与三阳病的浮、大、弦不同。沉对应浮，微对应大，细对应弦，这就是少阴脉。出现这种脉象，就可以识别出三阴病的端倪。至于少阴病的症状，有寒、热两种邪气，原本并不完全相同。这里姑且选取两种邪气侵入后出现的共同症状，那就是“但欲寐”。肾主管智慧巧思，热邪侵入扰乱其阴，寒邪侵入混淆其阳，因而导致只想睡觉。仲景先生教导人们，在未辨别寒热邪气之前，先辨别少阴病的症状，这是至关重要的诀窍。脉象沉、微、细，三阴病都有，如果兼见“但欲寐”，那就是少阴病。虽然沉、微、细三阴病皆有，但太阴病多见微脉，少阴病多见沉脉，厥阴病多见细脉。太阴位居中部，所以微脉多见；少阴位居下部，所以沉脉多见；厥阴靠近胆，所以弦脉可变细而细脉多见。盖因细脉即是轻微的弦脉。这也是为什么仲景在论述少阴病时，不说“沉”而反说“微细”的原因。“沉”是少阴的本脉，不必多说，而且“沉”也不是少阴独有的脉象，必须兼见太阴的微和厥阴的细，少阴的脉象才能确切。再者，少阴处于三阴之中，就像阳明处于三阳之中一样。阳明的脉象本为大，但如果兼见太阳的浮脉多，就是太阳阳明；兼见少阳的弦脉多，就是少阳阳明。推演到三阴，少阴的脉象，难道会例外吗？那么，少阴的沉脉兼见微脉多，不就是太阴的少阴吗？少阴的沉脉兼见细脉多，不就是厥阴的少阴吗？三阳中的阳明，从传经的角度来说，有相通的意义，所以仲景将其分为三类。三阴中的少阴，也是就传经而言，有相通的意义，为何不可引申呢？
【纲】张仲景说：少阴病，想吐却吐不出来，心烦，只想睡觉。过了五六天，出现自发性腹泻且口渴的，属于少阴病。这是因为虚，所以引水来自救。如果小便颜色发白的，少阴病的征象就全部具备了。小便发白，是因为下焦虚寒，不能制约水液，所以使小便颜色发白。
【目】王肯堂说：少阴病，像本条所述的各种症状，适用理中汤、四逆汤等方剂。阴症虽然常说不用麻黄，但如果少阴病刚得病，反而发热，脉象沉的，可用麻黄附子细辛汤。在六经病中，只有少阴病难以辨别。本经只说脉微细、想睡觉、小便频数且白、背部恶寒、四肢厥冷，可以不仔细审察就知道。或者虽然有严重的恶寒，却不觉得寒冷，只是喜欢穿厚衣服、靠近火源。其脉象微细，或沉涩。虽然有阴阳俱紧的情况，大概是因为病人素来有热，被表寒外袭，所以呈现这种情况。但应当以观察外在症状为主，必须用温药驱逐邪气。如果是阳邪传入，与少阴自身受热症状相合，适宜用下法、吐法或和解法的很多。仲景虽然没有明言滑、实、沉、数等可下的脉象，但结合症状是可以知道的，脉象必然相符。虽然有时会出现反常的沉、微、细、迟，脉象与症状不符，这是不可用下法，也宜用凉剂滋阴退阳而痊愈。如果不好转，必须等到脉象有力之后才可下。那些有症状显示需急下的，如果反而出现脉象与病情不符，也宜轻微攻下。虽然不敢大力攻下，也不可迟缓。六经病中只有少阴病的传变，与太阳病相同，如真武汤、四逆汤、通脉四逆汤的症状，都有加减法，谓或有或无的症状，也像小青龙汤、小柴胡汤一样。
【纲】张仲景说：脉象寸关尺三部都紧的，口中呼出的气多，嘴唇口舌干燥，鼻中流涕，身体蜷缩而卧，脚冷，舌上有滑苔，不要胡乱治疗。少阴病，腹泻，如果腹泻自行停止，恶寒且身体蜷缩而卧，手足温暖的，可以治愈。少阴病，恶寒，身体蜷缩而腹泻，手足逆冷的，无法治愈。
【目】沈金鳌按：第一条的蜷卧，是由于内寒。第二、三条也是同样的蜷卧，却以手足温暖或逆冷作为判断依据，以此说明可治与不可治的原因。大概温暖的是阳气回复，逆冷的是纯阴而无阳。
【纲】张仲景说：少阴病，脉象沉微细，只想睡觉，出汗且不烦躁，自己想要呕吐，到了第五六天，出现自发性腹泻，又烦躁，不能卧床睡眠的，预后不良（死）。
【目】陶华说：阳气虚，阴气盛，则眼睛闭合，所以多睡，这是邪气传入阴分而不在阳分。昏昏闭目，是阴气自然闭合的表现。默默不言，是阴气主静的表现。阳气盛，阴气虚，则昼夜不得眠。因为夜晚以阴为主，阴气盛则眼睛闭合但不安卧。如果阴被阳所胜，所以整夜烦扰而不能入睡。这就是所谓“阴虚则夜争”的情况。
[Outline] Zhang Zhongjing stated: The characteristic of Shaoyin disease is a pulse that is faint and fine, accompanied by a desire to sleep.
[Commentary] Fang Xingzhong said: A deep and fine pulse occurs because the Shaoyin meridian is located at the lowest part of the body, originating from below the little toe. The *Zhen Jing* (Classic of Acupuncture) states: "The Shaoyin meridian governs diseases generated by the Kidney," with symptoms including somnolence. Essentially, humans mirror Heaven and Earth. When Qi moves in the Yang aspect, it opens and becomes bright; when it moves in the Yin aspect, it closes and becomes dark. Thus, when human Qi moves in the Yang, one is active and awake; when it moves in the Yin, one is quiet and asleep. Therefore, "but wanting to sleep" (a state of lethargy/desire to sleep) indicates that pathogenic factors have lodged in the Yin aspect.
Wei Litong said: In Shanghan (Cold Damage) disease, transmission proceeds from the Three Yang meridians to the Three Yin meridians, passing from Taiyin to Shaoyin. This transmissive pathogen is an external contraction of wind-cold that has transformed into heat over time. There are also cases of direct invasion into the Shaoyin meridian and organs, which cannot be compared to transmissive heat pathogens; these belong to cold pathogens of Yin nature. Therefore, the Three Yang meridians are distinguished by meridian and fu-organ syndromes, while the Three Yin meridians are distinguished by meridian and zang-organ syndromes. For example, in Shaoyin disease, one must distinguish whether it is a transmissive heat pathogen or a directly invading cold pathogen. This specific clause summarizes the pulse and symptoms for both transmissive and direct-invading pathogens combined. In Shaoyin disease, the pulse must be deep. This applies to all Three Yin diseases, but here it is additionally faint and fine, differing from the floating, large, and wiry pulses of the Three Yang. Deep corresponds to floating, faint to large, and fine to wiry; this is the Shaoyin pulse. Observing this allows one to identify the beginnings of all Three Yin diseases. Regarding Shaoyin symptoms, there are cold and heat pathogens, which originally differ. Here, we select the common symptom appearing when either pathogen enters: "but wanting to sleep." The Kidney governs intellect and skill. Heat entering disturbs its Yin, while cold entering confuses its Yang, resulting in a desire to sleep. Master Zhongjing teaches that before distinguishing between cold and heat pathogens, one must first identify Shaoyin symptoms; this is a crucial principle. Pulses that are deep, faint, and fine appear in all Three Yin diseases; if accompanied by "but wanting to sleep," it is Shaoyin disease. Although deep, faint, and fine appear in all Three Yin, Taiyin often presents with faintness, Shaoyin with depth, and Jueyin with fineness. Taiyin is central, hence faintness is common; Shaoyin is lower, hence depth is common; Jueyin is near the Gallbladder, hence wiriness can transform into fineness, making fineness common. Fineness is essentially a mild form of wiriness. This explains why Zhongjing mentions "faint and fine" rather than "deep" for Shaoyin. "Deep" is the intrinsic pulse of Shaoyin and needs no special mention, nor is it unique to Shaoyin. It must be combined with Taiyin's faintness and Jueyin's fineness to definitively characterize the Shaoyin pulse. Furthermore, Shaoyin lies in the middle of the Three Yin, just as Yangming lies in the middle of the Three Yang. Yangming's pulse is inherently large; if combined with Taiyang's floating, it is Taiyang-Yangming; if combined with Shaoyang's wiriness, it is Shaoyang-Yangming. By analogy, how could Shaoyin's pulse be different? Thus, Shaoyin's depth combined with faintness resembles Taiyin-Shaoyin; Shaoyin's depth combined with fineness resembles Jueyin-Shaoyin. Yangming among the Three Yang, discussed via transmission, shares commonalities, so Zhongjing divided it into three categories. Shaoyin among the Three Yin, also discussed via transmission, shares commonalities; why not extend this logic?
[Outline] Zhang Zhongjing stated: In Shaoyin disease, there is a desire to vomit without actually vomiting, mental restlessness (irritability), and a desire to sleep. After five or six days, spontaneous diarrhea accompanied by thirst indicates involvement of the Shaoyin. This is due to deficiency, prompting the patient to seek water for self-rescue. If the urine is colorless/white, the manifestations of Shaoyin disease are fully present. Urine whiteness results from deficiency and cold in the Lower Jiao (Lower Burner), which fails to control water metabolism, causing the urine to appear white.
[Commentary] Wang Kentang said: For Shaoyin disease presenting with the symptoms described above, formulas such as Lizhong Tang (Regulate the Middle Decoction) and Sini Tang (Frigid Extremities Decoction) are appropriate. Although Yin syndromes generally do not use Mahuang (Ephedrae Herba), if Shaoyin disease is newly acquired and presents with fever and a deep pulse, Mahuang Fuzi Xixin Tang (Ephedra, Prepared Aconite, and Asarum Decoction) should be used. Among the Six Meridians, Shaoyin is the most difficult to differentiate. The classic text mentions only faint/fine pulse, somnolence, frequent/colorless urine, aversion to cold on the back, and cold limbs, which can be recognized without extensive examination. Even if severe aversion to cold exists, the patient may not feel cold but prefers thick clothing and proximity to fire. The pulse may be faint/fine or deep/choppy. Although a tight pulse in both Yin and Yang positions may occur, it is likely due to pre-existing internal heat combined with external cold attack. One must primarily observe external symptoms and treat with warming herbs to expel the pathogen. If Yang pathogens transmit inward, combining with Shaoyin heat syndromes, purgative, emetic, or harmonizing methods are often suitable. Although Zhongjing did not explicitly list slippery, solid, deep, or rapid pulses as indications for purgation, they can be inferred from symptoms, as the pulse must correspond. Occasionally, a deep, faint, fine, or slow pulse may contradict the symptoms, indicating that purgation is contraindicated; instead, cooling herbs to nourish Yin and subdue Yang should be used. If recovery does not occur, purgation may only be considered once the pulse becomes forceful. In cases requiring urgent purgation despite symptoms, if the pulse contradicts the illness, mild purgation is still necessary. While heavy purgation is avoided, delay is unacceptable. Among the Six Meridians, only Shaoyin transmission resembles Taiyang; conditions treated with Zhenwu Tang (True Warrior Decoction), Sini Tang, and Tongmai Sini Tang (Pulse-Unblocking Frigid Extremities Decoction) all include modification rules for varying symptoms, similar to Xiao Qinglong Tang (Minor Green Dragon Decoction) and Xiao Chaihu Tang (Minor Bupleurum Decoction).
[Outline] Zhang Zhongjing stated: When the pulse is tight in both Yin and Yang positions, there is excessive exhalation, dry lips and mouth, nasal discharge, curling up to lie down, cold feet, and a slippery coating on the tongue. Do not treat recklessly. In Shaoyin disease, if diarrhea stops spontaneously, and the patient has aversion to cold, curls up to lie down, but hands and feet are warm, the condition is treatable. In Shaoyin disease, if there is aversion to cold, curling up, diarrhea, and cold extremities (reversal cold), the condition is untreatable.
[Commentary] Shen Jin'ao noted: The curling up in the first clause is due to internal cold. The second and third clauses also feature curling up, but the prognosis depends on whether the hands and feet are warm or cold. Warmth indicates the return of Yang; reversal cold indicates pure Yin without Yang.
[Outline] Zhang Zhongjing stated: In Shaoyin disease, with a deep, faint, and fine pulse, a desire to sleep, sweating without irritability, and a desire to vomit, if by the fifth or sixth day spontaneous diarrhea occurs, followed by irritability and inability to sleep, death ensues.
[Commentary] Tao Hua said: When Yang Qi is deficient and Yin Qi is abundant, the eyes close, leading to excessive sleepiness; this indicates the pathogen has transmitted to the Yin and is no longer in the Yang. Drowsiness with closed eyes reflects the natural closing of Yin. Silence reflects the quiet nature of Yin. Conversely, when Yang Qi is abundant and Yin Qi is deficient, sleep is impossible day or night. Night belongs to Yin; if Yin is abundant, the eyes close but restlessness prevents sleep. If Yin is overcome by Yang, there is whole-night irritability and insomnia, known as "Yin deficiency leads to nightly contention."
Shen Jin'ao noted: Initially desiring to sleep is the intrinsic symptom of Shaoyin. Inability to sleep after five or six days indicates the imminent extinction of slight Yang Qi. How can life be sustained?