少阳之为病，口苦、咽干、目眩也。
太阳主表，头项强痛为提纲。阳明主里，胃家实为提纲。少阳居半表半里之位，仲景特揭口苦、咽干、
目眩为提纲，奇而至当也。盖口、咽、目三者，不可谓之表，又不可谓之里，是表之入里、里之出表处，所谓半
表半里也。三者能开能阖，开之可见，阖之不见，恰合枢机之象，故两目为少阳经络出入之地。苦、干、眩者，
皆相火上走空窍而为病也。此病自内之外，人所不知，惟病患独知，诊家所以不可无问法。三证为少阳一经病机，
兼风寒杂病而言。但见一证即是，不必悉具。
伤寒脉弦细头痛发热者，属少阳。少阳不可发汗，发汗则谵语。此属胃，胃和则愈，胃不和则烦而躁。
少阳初受寒邪，病全在表，故头痛发热与太阳同，与五六日而往来寒热之半表不同也。弦为春脉，细则少
阳初出之象也。但见头痛发热，而不见太阳脉证，则弦细之脉，断属少阳，而不可作太阳治之矣。少阳少血，虽有
表证，不可发汗。发汗则津液越出，相火燥必胃实而谵语，当与柴胡以和之。上焦得通，津液得下，胃气因和。
若加烦躁，则为承气证矣。
少阳中风，两耳无所闻，目赤，胸中满而烦者，不可吐、下，吐、下则悸而惊。
少阳经络，索于头目，循于胸中，为风木之藏，主相火。风中其经，则风动火炎，是以耳聋目赤，胸满而烦
也。耳目为表之里，胸中为里之表，当用小柴胡和解法。或谓热在上焦，因而越之，误吐者有矣；或谓釜底抽
薪，因而夺之，误下者有矣；或谓火郁宜发，因而误汗者有矣。少阳主胆，胆无出入，妄行吐、下，津液重亡。
胆虚则心亦虚，所生者受病，故悸也；胆虚则肝亦虚，府病及藏，故惊也。上条汗后而烦，因于胃实；此未汗而
烦，虚风所为。上条烦而躁，病从胃来；此悸而惊，病迫心胆。上条言不可发汗，此言不可吐、下，互相发明，
非谓中风可汗，而伤寒可吐、下也。此虽不言脉，可知其弦而浮矣。不明少阳脉
证，则不识少阳中风；不辨少阳脉状，则不识少阳伤寒也。
伤寒三日，少阳脉小者，欲已也。
阳明受病，当二三日发；少阳受病，当三四日发。若三日脉大，则属阳明；三日弦细，则属少阳。小即细也，
若脉小而无头痛发热等证，是少阳不受邪。此即伤寒三日，少阳证不见，为不传也。
少阳病，欲解时，从寅至辰上。
寅、卯主木，少阳始生，即少阳主时也。主气旺，则邪自解矣。辰上者，卯之尽，辰之始也。
太阳与少阳并病，脉弦，头项强痛，或眩冒，时如结胸，心下痞硬者，当刺大椎第一间、肺俞、肝俞。慎
不可发汗，发汗则谵语。若谵语不止，当刺期门。
脉弦属少阳，头项强痛属太阳。眩冒、结胸、心下痞，则两阳皆有之证。两阳并病，阳气重可知。然是经
脉之为眚，汗吐下之法，非少阳所宜。若不明刺法，不足以言巧。督主诸阳，刺大椎以泄阳气。肺主气，肝主
血，肺肝二俞，皆主太阳。调其气血，则头项强痛可除，脉之弦者可和，眩冒可清，结胸、痞硬等证可不至矣。
若发汗是犯少阳，胆液虚必转属胃而谵语。此谵语虽因胃实。而两阳之证未罢，亦非下法可施也。土欲实，木
当平之，必肝气清而水土治，故刺期门而三阳自和。
太阳少阳并病，心下硬，头项强而眩者，当刺大椎、肺俞、肝俞，慎勿下之。
太阳少阳并病，而反下之，成结胸，心下硬，下利不止，水浆不下，其人心烦。
并病无结胸证，但阳气怫郁于内，时时若结胸状耳，并病在两阳，而反下之如结胸者，成真结胸矣。结胸
法当下。今下利不止，水浆不入，是阳明之阖病于下，太阳之开病于上，少阳之枢机无主。其人心烦，是结胸
证具，烦躁者死也。
太阳经主管体表，其提纲证是头项部僵硬疼痛。阳明经主管体内，其提纲证是胃肠实热积滞。少阳经位于半表半里的位置，张仲景特别提出口苦、咽干、目眩作为少阳病的提纲，这看似奇特却极为恰当。因为口、咽、目这三个部位，不能称之为表，也不能称之为里，它们是表进入里、里出于表的过渡地带，也就是所谓的“半表半里”。这三个部位既能开启也能闭合，开启时可见，闭合时不可见，恰好符合枢机（枢纽机制）的形象，所以两眼是少阳经络出入的地方。口苦、咽干、目眩，都是相火（少阳之火）上走空窍而导致的病变。这种病由内向外发展，外人不知，只有患者自己清楚，因此医生在诊断时不可忽视问诊的方法。这三种证候是少阳一经的病机关键，同时也兼及风寒等杂病。只要见到其中一种证候即可诊断为少阳病，不必所有症状都具备。
伤寒病出现脉象弦细、头痛、发热的，属于少阳病。少阳病禁止使用发汗法，如果误用发汗法，会导致胡言乱语（谵语）。这种情况归属于胃，胃气调和则病愈，胃气不和则会出现心烦和躁动。
少阳病初受寒邪时，病邪完全在表，所以头痛发热与太阳病相同，这与发病五六日后出现的往来寒热的半表半里证是不同的。弦脉是春季的脉象，细脉是少阳病初起外出的征象。如果只见到头痛发热，而没有太阳病的脉证，那么弦细的脉象就断定属于少阳病，而不能当作太阳病来治疗了。少阳经气血相对较少，即使有表证，也不可使用发汗法。如果误用发汗法，津液就会外泄，相火燥盛会致使胃中实热而出现谵语，此时应当给予小柴胡汤来调和。上焦通畅，津液得以下行，胃气因而调和。如果再加上烦躁，那就变成了承气汤证的范畴了。
少阳经受风邪侵袭，出现两耳听不见、眼睛发红、胸中满闷且心烦的症状，禁止使用催吐法和泻下法，如果误用吐、下法，会导致心悸和惊恐。
少阳经络分布于头目，循行于胸中，少阳属风木之脏，主司相火。风邪侵入其经络，则风动火炎，从而导致耳聋、目赤、胸满而烦。耳目位于表的内部，胸中位于里的外部，此时应当采用小柴胡汤进行和解治疗。有人说热邪在上焦，应该用涌吐法使其排出，这是误用吐法的例子；有人说像釜底抽薪一样，应该用攻下法祛除邪气，这是误用下法的例子；有人说火郁应当发散，于是误用发汗法，这也是错误的。少阳主胆，胆没有直接的出入通道，妄用吐、下法会导致津液严重耗损。胆气虚弱则心气也虚，心为胆之所生，受病故出现心悸；胆气虚弱则肝气也虚，腑病波及脏，故出现惊恐。上一条文中提到发汗后出现烦躁，是因为胃实；这里未发汗而出现的烦躁，是由于虚风所致。上一条文中提到的烦而躁，病源来自胃；这里的心悸和惊恐，病势逼迫心胆。上一条文说不可发汗，这里说不可吐、下，两者互相阐发，并不是说中风可以发汗，而伤寒可以吐、下。这里虽然没有提及脉象，但可以推断其脉象应为弦而浮。如果不明了少阳的脉证，就无法识别少阳中风；如果不辨别少阳的脉状，就无法识别少阳伤寒。
伤寒病程到了第三天，如果少阳脉象变小，说明病情将要痊愈。
阳明经受病，通常在第二三天发作；少阳经受病，通常在第三四天发作。如果第三天脉象盛大，则属于阳明病；如果第三天脉象弦细，则属于少阳病。小脉即细脉，如果脉象细小且没有头痛发热等症状，说明少阳未受邪气侵犯。这就是所说的“伤寒三日，少阳证不见”，意味着病邪没有传变到少阳。
少阳病欲缓解的时间，是从寅时到辰时这段时间。
寅时、卯时主木，少阳气始生，即少阳主令之时。当少阳主气旺盛时，邪气自然解除。辰时是卯时的结束，辰时的开始。
太阳病与少阳病并病，脉象弦，头项僵硬疼痛，有时出现眩晕昏冒，有时感觉像结胸证，心下部痞塞硬满的，应当针刺大椎穴第一间隙、肺俞穴、肝俞穴。千万不可发汗，如果发汗会导致谵语。如果谵语不止，应当针刺期门穴。
脉弦属于少阳，头项强痛属于太阳。眩晕昏冒、结胸、心下痞，则是太阳和少阳两经都有的证候。两阳并病，阳气亢盛可知。但是本经脉的病变，汗、吐、下这些治法，都不适合少阳病。如果不明白针刺疗法，不足以称为医术精巧。督脉统领诸阳，针刺大椎以宣泄阳气。肺主气，肝主血，肺俞和肝俞都与太阳经有关。调理气血，则头项强痛可除，脉象之弦可和，眩晕昏冒可清，结胸、痞硬等证候就不会出现了。如果发汗就是触犯少阳禁忌，胆液虚弱必然转属胃腑而导致谵语。这种谵语虽然因胃实引起，但两阳的证候尚未罢除，也不是下法可以施用的。土（脾胃）欲实，木（肝胆）应当平抑它，必须使肝气清肃，水土才能治理，所以针刺期门穴，三阳经气自然调和。
太阳病与少阳病并病，心下部硬满，头项强痛且眩晕的，应当针刺大椎穴、肺俞穴、肝俞穴，千万不要使用泻下法。
太阳病与少阳病并病，反而使用泻下法，会形成结胸证，表现为心下部硬满，腹泻不止，水浆无法入口，病人心中烦乱。
并病原本没有结胸证，只是阳气怫郁在内，时时感觉像结胸的样子罢了。并病发生在两阳经，如果反而使用泻下法导致像结胸一样的情况，就变成了真正的结胸证。结胸证依法应当使用下法。现在腹泻不止，水浆不入，这是阳明阖病在下，太阳开病在上，少阳枢机失去主宰。病人心中烦乱，说明结胸证已完备，出现烦躁者预后不良，多致死。
Shaoyang disease is characterized by a bitter taste in the mouth, dryness of the throat, and vertigo.
The Taiyang (Greater Yang) channel governs the exterior, with its guiding syndrome being stiffness and pain in the head and nape. The Yangming (Yang Brightness) channel governs the interior, with its guiding syndrome being excess in the stomach and intestines. Shaoyang (Lesser Yang) occupies the position between the exterior and the interior. Zhang Zhongjing specifically highlights bitter taste, dry throat, and vertigo as the guiding syndrome for Shaoyang; this appears unique but is highly appropriate. The mouth, throat, and eyes cannot be classified strictly as exterior or interior; they are the transition zone where the exterior enters the interior and the interior emerges to the exterior, known as "half-exterior half-interior." These three sites can open and close; when open, they are visible; when closed, they are not, which perfectly matches the image of the pivot mechanism (Shu Ji). Thus, the eyes are the places where the Shaoyang meridians enter and exit. Bitter taste, dryness, and vertigo are all diseases caused by Ministerial Fire (Xiang Huo) ascending to the orifices. This disease develops from the inside out; it is unknown to others but known only to the patient. Therefore, physicians must not neglect the method of inquiry (Wen Zhen). These three syndromes constitute the pathogenesis of the Shaoyang channel and also encompass wind-cold and miscellaneous diseases. If any one of these symptoms is present, it indicates Shaoyang disease; it is not necessary for all symptoms to be present.
In cold damage (Shang Han), if the pulse is wiry and fine, accompanied by headache and fever, it belongs to Shaoyang. Shaoyang disease prohibits sweating therapy. If sweating is induced erroneously, it leads to delirious speech (Chan Yu). This condition then pertains to the Stomach. If the Stomach Qi harmonizes, the disease resolves; if it does not harmonize, irritability and restlessness ensue.
When Shaoyang disease first receives cold pathogenic factors, the pathology is entirely at the exterior. Therefore, headache and fever are similar to Taiyang disease, differing from the alternating chills and fever seen after five or six days, which represents the half-exterior half-interior stage. A wiry pulse is the pulse of Spring; a fine pulse is the manifestation of Shaoyang initially emerging. If headache and fever are present without the pulse and syndromes of Taiyang, the wiry and fine pulse definitively indicates Shaoyang disease, and it should not be treated as Taiyang disease. Shaoyang has relatively less blood; even if there are exterior syndromes, sweating therapy is contraindicated. Erroneous sweating causes body fluids to leak out, leading to desiccation by Ministerial Fire, resulting in gastric excess and delirium. In such cases, Xiao Chai Hu Tang (Minor Bupleurum Decoction) should be administered to harmonize. When the Upper Jiao (Upper Burner) becomes unobstructed, body fluids descend, and Stomach Qi harmonizes. If irritability is added, it becomes a Cheng Qi Tang (Gangue Decoction) syndrome.
In Shaoyang wind strike, symptoms include bilateral deafness, red eyes, fullness in the chest, and irritability. Vomiting and purging therapies are contraindicated. Erroneous vomiting or purging leads to palpitations and fright.
The Shaoyang meridians traverse the head and eyes and circulate through the chest. As a Wind-Wood organ, Shaoyang governs Ministerial Fire. When wind pathogen invades the meridians, wind stirs and fire flares, causing deafness, red eyes, chest fullness, and irritability. The ears and eyes are interior to the exterior; the chest is exterior to the interior. The Xiao Chai Hu He Jie Fa (Harmonizing Method) should be used. Some argue that heat in the Upper Jiao should be expelled via emesis (Yue Zhi); this is an erroneous use of vomiting. Some argue for removing the firewood from under the cauldron (Fu Di Chou Xin) via purgation; this is an erroneous use of purging. Some argue that constrained fire should be dispersed via sweating; this is an erroneous use of sweating. Shaoyang governs the Gallbladder, which has no direct entry or exit. Reckless vomiting or purging causes severe loss of body fluids. When Gallbladder Qi is deficient, Heart Qi is also deficient; since the Heart is generated by the Liver/Wood, it suffers illness, causing palpitations. When Gallbladder Qi is deficient, Liver Qi is also deficient; Fu-organ disease affects the Zang-organ, causing fright. In the previous paragraph, irritability after sweating was due to gastric excess; here, irritability before sweating is due to deficient wind. In the previous paragraph, irritability and restlessness originated from the Stomach; here, palpitations and fright press upon the Heart and Gallbladder. The previous text states sweating is prohibited; this text states vomiting and purging are prohibited. They elucidate each other mutually. It does not mean wind strike can be sweated, nor that cold damage can be vomited or purged. Although the pulse is not mentioned here, it can be inferred to be wiry and floating. Without understanding Shaoyang pulses and syndromes, one cannot recognize Shaoyang wind strike; without distinguishing Shaoyang pulse characteristics, one cannot recognize Shaoyang cold damage.
In cold damage, on the third day, if the Shaoyang pulse is small, the disease is about to resolve.
Yangming disease typically manifests on the second or third day; Shaoyang disease typically manifests on the third or fourth day. If the pulse is large on the third day, it belongs to Yangming; if wiry and fine, it belongs to Shaoyang. Small means fine. If the pulse is small without symptoms like headache and fever, Shaoyang has not received the pathogen. This corresponds to "cold damage on the third day, without Shaoyang syndromes," indicating no transmission.
Shaoyang disease tends to resolve during the hours of Yin to Chen (3:00 AM to 7:00 AM).
Yin and Mao hours govern Wood, when Shaoyang Qi begins to generate; thus, Shaoyang governs this time. When the governing Qi is prosperous, the pathogen naturally resolves. Chen hour is the end of Mao and the beginning of Chen.
In concurrent Taiyang and Shaoyang disease, with a wiry pulse, stiffness and pain in the head and nape, occasional vertigo and dizziness, sensations resembling Jie Xiong (Chest Binding), and hardness and stuffiness below the heart, one should puncture the first interspace of the Dazhui (GV14) point, Feishu (BL13), and Ganshu (BL18). Sweating therapy must be strictly avoided. If sweating induces delirium, and it persists, Qimen (LR14) should be punctured.
A wiry pulse belongs to Shaoyang; head and nape stiffness belong to Taiyang. Vertigo, Chest Binding, and epigastric stuffiness are syndromes common to both Yang channels. In concurrent Yang disease, excessive Yang Qi is evident. However, for pathology in this meridian, sweating, vomiting, and purging methods are unsuitable for Shaoyang. Without mastering acupuncture, one cannot claim skillful medicine. The Du Mai (Conception Vessel of the Back) governs all Yang meridians; puncturing Dazhui drains Yang Qi. The Lung governs Qi, and the Liver governs Blood. Both Feishu and Ganshu relate to Taiyang. Regulating Qi and Blood removes head and nape stiffness, harmonizes the wiry pulse, clears vertigo, and prevents Chest Binding and epigastric hardness. If sweating is performed, it violates Shaoyang restrictions. Gallbladder fluid deficiency leads to transmission to the Stomach and delirium. Although this delirium stems from gastric excess, the concurrent Yang syndromes have not resolved, so purging is not applicable. Earth (Spleen/Stomach) desires excess; Wood (Liver/Gallbladder) should level it. Only when Liver Qi is clear can Water and Earth be regulated. Thus, puncturing Qimen harmonizes the Three Yang channels.
In concurrent Taiyang and Shaoyang disease, with epigastric hardness, head and nape stiffness, and vertigo, one should puncture Dazhui, Feishu, and Ganshu. Purging must be strictly avoided.
If concurrent Taiyang and Shaoyang disease is erroneously purged, it results in Jie Xiong (Chest Binding), characterized by epigastric hardness, incessant diarrhea, inability to take food or drink, and mental restlessness.
Concurrent disease does not originally present with Jie Xiong; it merely involves Yang Qi stagnation internally, occasionally resembling Chest Binding. Concurrent disease affects two Yang channels. Erroneous purging transforming it into true Jie Xiong creates a critical situation. Jie Xiong legally requires purging. However, now with incessant diarrhea and inability to ingest fluids, it indicates Yangming's closing function failing below, Taiyang's opening function failing above, and Shaoyang's pivot mechanism losing control. Mental restlessness indicates complete Jie Xiong syndrome; irritability combined with restlessness signifies death.