《难经》曰∶伤寒之脉，阴阳俱盛而紧涩。《伤寒论》云∶脉阴阳俱紧者，名曰伤寒。
寸口脉浮而紧，浮则为风，紧则为寒。浮涩而紧为伤寒。脉沉微而热不退者危。
陶节庵曰∶凡热证有头疼恶寒，皆是伤寒，无则皆非也，何则？伤寒则恶寒，伤食则
恶食，理固然也。但在冬时恶寒为甚，盖冬为正伤寒，天气严凝，风寒猛烈，触冒之者，恶寒殊
甚，其余时月恶寒亦微。冬时恶寒，腠理闭密，非辛温不可，故以桂枝等药以治之。然风与寒
常相因，寒则伤荣，恶寒头痛脉浮而无汗，则用麻黄汤开发腠理，以散邪，得汗则愈。风则
伤卫，头痛恶风，脉浮缓而自汗，则用桂枝汤充塞腠理以散邪，汗止即愈。若夫荣卫俱伤，又非
此二汤所治也，须大青龙汤。然此汤大峻，其可代之者，有非冬时恶寒头痛之证，皆宜辛凉
之剂，通表里以和之则愈矣。若以冬时所用桂枝辛凉之药而通治之，则杀人矣。曰辛凉者何？
羌活冲和汤是也，兼能代大青龙汤为至稳。过此则少阳阳明二经在乎半表里肌肉之间，脉亦不浮
不沉。外证在阳明则有目疼鼻干，不得眠之证，脉洪而长，以葛根解肌汤、升麻汤治之。在少
阳则胸胁痛而耳聋，脉见弦数，以小柴胡加减以和之。此三经者，不从标本，从乎中也。以小
柴胡汤加葛根芍药，治少阳阳明俱病如拾芥。若传入里，外证悉罢，已无头痛恶寒，脉见沉实，
便作实热谵语恶热，六七日不大便，口燥咽干而渴，轻则大柴胡汤，重则三承气汤。选用比之
大人，剂惟轻缓而治之可也。
麻黄汤（治伤寒头痛，发热腰痛，骨节痛，恶寒无汗而喘，以此汗之，盖暖取汗
至手足心而止，不须再服。）
桂枝汤（伤寒发热恶寒有汗，以此和之。此为表虚不可再汗。）
大青龙汤（治伤寒脉浮紧，头痛身痛，发热恶寒，不得汗出烦躁，扰乱不安，以此汗之。）
羌活冲和汤（治太阳经伤寒无汗，发热头痛，恶寒脊强，脉浮紧，又治非冬时或有暴寒中
人，如伤寒者，以此治之万全。此方代麻黄汤用极平稳无害。）
解肌汤（治温病天行时气，头痛壮热，四时感冒，发热而渴，不恶寒者用此。）
升麻汤（治伤寒头痛，憎寒壮热，四肢疼痛，鼻干不卧，兼治四时感冒，不正之气，忽然恶寒头重。）
败毒散（伤寒风温瘟疫，头目昏眩，四肢疼痛，憎寒壮热，项强目疼。）
小柴胡汤（治伤寒要药，不俱少阳，和解、表解有碍者，多宜用之，无误。在小儿尤为平
剂。已上方并见大人伤寒门。）
一、伤寒五六日，往来寒热，胸胁苦痛，默默悸欲食，心烦喜呕，或胸膈烦而不呕，
或渴，或腹中痛，或胁下痞，或心下悸，小便不利，或不渴身有微热者，此汤主之。
一、气虚血弱，腠理开，邪气因入与正气相搏，结于胁下，邪正分争，往来寒热，休作
有时，此汤主之。
一、伤寒五六日，头汗出，微恶寒，心下满，不欲食，不便硬，脉细者，为阳微阴结，
必有表复有里，脉沉亦在里，汗出为阳微。假令纯阴结，不得复有外证，悉入在里，此为半在表，半
在里也。脉虽沉紧，不得为少阴病。所以然者，阴不得有汗也。今头汗出，故知非少阴也。
此汤主之。
一、阳明病发潮热，大便溏，小便少，胸膈满，此汤与之。
一、阳明病胁下硬满，不大便而呕，舌上白苔者，此与之。
一、太阳病不解，病过十日转入少阳，胁下硬满，呕不能食，往来寒热，尚未吐下，脉沉
紧者，此汤主之。
一、伤寒瘥后，复更发热，此汤主之。
大柴胡汤 治阳明病外证，身热汗出而不恶寒，但恶热，宜服此。阳明病脉逆发热，汗出
而不恶寒，头眩小便难，此欲发疽证，宜服此。阳明病，胁下硬满，大便秘而呕，口燥者，
此汤服之。阳明病中风，其脉浮大，气短心痛，鼻干嗜卧不得汗，一身尽黄，小便难，有潮
热而哕，此汤主之。
一、伤寒胁下坚满，少阴干呕，不食，往来寒热，若未吐下，此汤服之。若已吐下发
汗谵语者，此汤主之。
一、伤寒五六日，阳脉涩，阴脉弦，腹中急痛，此汤主之。
一、伤寒六七日，目中不了了，无表里证，大便难，身微热，此汤主之。
小承气汤 治太阳吐下而微烦，小便数，大便坚者，与此。上焦热壅，胸痞而实，故用枳
实、浓朴以泻上焦之痞，大黄泻实，去芒硝不伤阴分之血也。
大承气汤 治伤寒里实，三焦俱热，腹满而喘者，宜服此汤。
调胃承气汤 治伤寒十余日，不恶寒但恶热者，实也。腹中满不大便，蒸蒸郁郁者，宜用之。
已上诸方并见大人伤寒门，若小儿剂比大人减半，或三分之二与之。
The *Nan Jing* (Classic of Difficult Issues) states: In Shanghan (Cold Damage), the pulse is vigorous and tight in both Yin and Yang positions. The *Shanghan Lun* (Treatise on Cold Damage Disorders) says: When the pulse is tight in both Yin and Yang positions, it is named Shanghan (Cold Damage).
If the Cun Kou (radial artery at the wrist) pulse is floating and tight, floating indicates Wind pathogen, and tight indicates Cold pathogen. A pulse that is floating, choppy, and tight indicates Shanghan (Cold Damage). If the pulse is deep and faint while fever persists, the condition is critical.
Tao Jie'an stated: Any heat syndrome presenting with headache and aversion to cold is Shanghan (Cold Damage); if these are absent, it is not. Why? Because Shanghan (Cold Damage) causes aversion to cold, whereas food stagnation causes aversion to food; this is logical. However, during winter, aversion to cold is particularly severe because winter is the season for true Shanghan (Cold Damage). The weather is freezing and condensed, and the wind-cold is fierce. Those who contract it experience severe aversion to cold. In other seasons, aversion to cold is milder. During winter, when aversion to cold occurs, the Cou Li (pores and interstices) are closed and dense, requiring acrid-warm herbs; thus, herbs like Guizhi Tang (Cinnamon Twig Decoction) are used. However, Wind and Cold often accompany each other. Cold damages Ying Qi (Nutritive Qi); if there is aversion to cold, headache, a floating pulse, and no sweating, Mahuang Tang (Ephedra Decoction) is used to open the Cou Li (pores and interstices) and disperse the pathogen. Recovery occurs after sweating. Wind damages Wei Qi (Defensive Qi); if there is headache, aversion to wind, a floating and moderate pulse, and spontaneous sweating, Guizhi Tang (Cinnamon Twig Decoction) is used to fill the Cou Li (pores and interstices) and disperse the pathogen. Recovery occurs when sweating stops. If both Ying Qi (Nutritive Qi) and Wei Qi (Defensive Qi) are damaged, neither of these two decoctions is suitable; Da Qing Long Tang (Major Blue Green Dragon Decoction) must be used. However, this decoction is very potent. Alternatives exist: for cases occurring outside winter with aversion to cold and headache, acrid-cool agents should be used to harmonize the interior and exterior. Using winter-specific acrid-cool herbs like those in Guizhi Tang (Cinnamon Twig Decoction) indiscriminately would be fatal. What are acrid-cool agents? Huoqu Chonghe Tang (Notopterygium Harmonizing Decoction) is one; it can safely replace Da Qing Long Tang (Major Blue Green Dragon Decoction). Beyond this stage, Shaoyang (Lesser Yang) and Yangming (Yang Brightness) meridians involve pathogens located between the exterior and interior within the muscles, and the pulse is neither floating nor deep. Exterior manifestations in Yangming include eye pain, dry nose, and insomnia, with a surging and long pulse; Gegen Ji Ji Tang (Kudzu Muscle-Releasing Decoction) and Shengma Tang (Cimicifuga Decoction) are used. Manifestations in Shaoyang include chest and hypochondriac pain and deafness, with a wiry and rapid pulse; Xiaochaihu Tang (Minor Bupleurum Decoction) modified is used to harmonize. These three meridians are treated via "Zhong" (the middle/harmonizing method) rather than Biao (exterior) or Ben (root). Using Xiaochaihu Tang (Minor Bupleurum Decoction) added with Gegen (Kudzu Root) and Shaoyao (Peony Root) treats concurrent Shaoyang and Yangming diseases as easily as picking up grass. If the pathogen transmits to the interior, all exterior signs cease, headache and aversion to cold disappear, and the pulse becomes deep and solid. Symptoms turn into excess heat, delirium, aversion to heat, constipation for six to seven days, dry mouth, parched throat, and thirst. Mild cases are treated with Dahuang Tang (Major Rhubarb Decoction - *Note: Text implies Dahuang Chaihu Tang contextually but names generic*, actually text says Dahuang Tang which usually refers to Dahuang Chaihu Tang in this sequence or similar, but strictly translating text: Dahuang Tang), and severe cases with the Three Chengqi Decoctions. Dosages for children should be reduced and moderated compared to adults.
Mahuang Tang (Ephedra Decoction): Treats Shanghan (Cold Damage) with headache, fever, lower back pain, bone and joint pain, aversion to cold, anhidrosis, and wheezing. Induces sweating by keeping warm until sweat appears on the palms and soles; do not administer further doses.
Guizhi Tang (Cinnamon Twig Decoction): Treats Shanghan (Cold Damage) with fever, aversion to cold, and sweating. Harmonizes the body. This is a deficiency exterior pattern; do not induce sweating again.
Da Qing Long Tang (Major Blue Green Dragon Decoction): Treats Shanghan (Cold Damage) with a floating-tight pulse, headache, body pain, fever, aversion to cold, anhidrosis, restlessness, and agitation. Induces sweating.
Huoqu Chonghe Tang (Notopterygium Harmonizing Decoction): Treats Taiyang (Greater Yang) Shanghan (Cold Damage) with anhidrosis, fever, headache, aversion to cold, stiff neck, and floating-tight pulse. Also treats non-winter sudden cold invasion mimicking Shanghan (Cold Damage). It is safe and effective, serving as a gentle substitute for Mahuang Tang (Ephedra Decoction).
Ji Ji Tang (Muscle-Releasing Decoction): Treats Wen Bing (Warm Diseases), epidemic febrile diseases, severe headache, high fever, seasonal colds, fever with thirst, and absence of aversion to cold.
Shengma Tang (Cimicifuga Decoction): Treats Shanghan (Cold Damage) with headache, severe aversion to cold and high fever, limb pain, dry nose, insomnia. Also treats seasonal colds caused by abnormal qi, sudden aversion to cold, and heavy head.
Baidu San (Poison-Resolving Powder): Treats Shanghan (Cold Damage), Feng Wen (Wind Warmth), and plague with dizziness, limb pain, severe aversion to cold and high fever, stiff neck, and eye pain.
Xiaochaihu Tang (Minor Bupleurum Decoction): A key herb/decoction for Shanghan (Cold Damage). Suitable for Shaoyang (Lesser Yang) disorders and cases where harmonization or exterior resolution is obstructed. Safe for children. See Adult Shanghan (Cold Damage) section for details.
1. After five to six days of Shanghan (Cold Damage), alternating chills and fever, bitter distension in the chest and hypochondrium, silent mood, palpitations, desire to eat, irritability, and frequent vomiting. Or, chest diaphragm vexation without vomiting, thirst, abdominal pain, hypochondriac fullness, epigastric palpitations, difficult urination, or no thirst with slight body heat. This decoction governs.
2. With Qi deficiency and Blood weakness, the Cou Li (pores and interstices) are open, allowing pathogens to enter and clash with healthy Qi, knotting in the hypochondrium. Pathogen and healthy Qi struggle, causing alternating chills and fever with regular intervals. This decoction governs.
3. After five to six days of Shanghan (Cold Damage), sweating only on the head, slight aversion to cold, epigastric fullness, loss of appetite, hard stool, and fine pulse indicate Yang deficiency and Yin knotting. There is both exterior and interior involvement. Deep pulse indicates interior. Sweating indicates Yang deficiency. Pure Yin knotting would have no exterior signs. Thus, it is half-exterior, half-interior. Even with a deep-tight pulse, it is not Shaoyin (Lesser Yin) disease because Yin patterns do not sweat. Head sweating confirms it is not Shaoyin. This decoction governs.
4. Yangming disease with tidal fever, loose stools, scanty urine, and chest/diaphragm fullness. This decoction is given.
5. Yangming disease with hardness/fullness in the hypochondrium, constipation, vomiting, and white tongue coating. This decoction is given.
6. Taiyang (Greater Yang) disease unresolved, turning into Shaoyang (Lesser Yang) after ten days, with hardness/fullness in the hypochondrium, vomiting, inability to eat, alternating chills and fever, no prior purgation or emesis, and a deep-tight pulse. This decoction governs.
7. Fever recurring after recovery from Shanghan (Cold Damage). This decoction governs.
Dahuang Chaihu Tang (Major Rhubarb and Bupleurum Decoction): Treats Yangming exterior syndrome with body heat, sweating, no aversion to cold, but aversion to heat. Also treats Yangming with reversed pulse, fever, sweating, no aversion to cold, dizziness, and difficult urination (precursor to abscess). Treats Yangming with hypochondriac hardness, constipation, vomiting, and dry mouth. Treats Yangming Wind strike with floating-large pulse, shortness of breath, heart pain, dry nose, lethargy, anhidrosis, generalized jaundice, difficult urination, tidal fever, and hiccups.
1. Shanghan (Cold Damage) with hardness/fullness in the hypochondrium, Shaoyin (Lesser Yin) dry retching, anorexia, and alternating chills and fever. If no prior emesis/purgation, take this decoction. If already vomited/purged/sweated leading to delirium, this decoction governs.
2. After five to six days of Shanghan (Cold Damage), superficial pulse is choppy, deep pulse is wiry, with acute abdominal pain. This decoction governs.
3. After six to seven days of Shanghan (Cold Damage), unclear vision, no exterior/interior signs, difficult defecation, slight body heat. This decoction governs.
Xiao Chengqi Tang (Minor Bowel-Unblocking Decoction): Treats Taiyang (Greater Yang) post-emesis/purgation with mild vexation, frequent urination, and hard stool. Clears upper Jiao (Triple Burner) heat obstruction and chest fullness using Zhishi (Immature Bitter Orange) and Houpo (Magnolia Bark) to drain upper Jiao stagnation, and Dahuang (Rhubarb) to drain excess, omitting Mangxiao (Mirabilite) to protect Yin blood.
Da Chengqi Tang (Major Bowel-Unblocking Decoction): Treats Shanghan (Cold Damage) interior excess with heat in all three Jiao (Triple Burners), abdominal fullness, and wheezing.
Tiaowei Chengqi Tang (Regulating Stomach Bowel-Unblocking Decoction): Treats Shanghan (Cold Damage) after ten-plus days, no aversion to cold but aversion to heat, indicating excess. Abdominal fullness, constipation, and oppressive heat. Use this decoction.
All above formulas are in the Adult Shanghan (Cold Damage) section. For children, reduce dosage by half or two-thirds.