秦子曰∶中寒之症，身不发热，手足厥冷，二便清利，即仲景直中阴经之真阴症也。若
恶寒发热，则伤寒阳症，而非中寒症矣。故仲景以恶寒发热者，名曰伤寒，曰阳症；以恶寒
不发热者，名曰中寒，曰阴症。今余以直中阴经之阴症，立其名曰中寒；以寒伤三阳之阳症
，名曰伤寒，则阳症不混于阴症条内。
【中寒之症】恶寒身蜷，遍身疼痛，或自下利，口有冷涎，面如刀刮，手足厥冷，无
热神清，唇不焦，口不渴，二便清白，此中寒之症也。
【中寒之因】其人真阳素虚，阴寒内盛，胃中之阳，不能捍卫于外；脾中之阳，不能
腐熟于中；肾中之阳，不能封闭关门；一得外寒，则直中三阴，而为中寒之症矣。
【中寒之脉】脉多沉微，或微而迟，或极似绝，或伏而沉。或空而浮，或紧而弦。
【中寒之治】寒中少阴，二三日应微汗者，麻黄附子甘草汤。又少阴身痛手足寒，脉
沉者，附子汤。若下利脉微，白通汤；若利不止，厥逆无脉，干呕而烦者，白通汤加猪胆汁以止
烦。又少阴下利，有水气，或咳或呕，真武汤。又太阴自利不渴，其人脏有寒也，用四逆汤
以温之。若厥阴下利，四肢疼，厥逆恶寒，四逆汤。又厥阴下利清谷，汗出而厥，通脉四逆
麻黄附子甘草汤
麻黄 附子 甘草
附子汤
熟附子 白术 白茯苓 人参 白芍药
白通汤
葱白 干姜 熟附子
白通猪胆汤
葱白 干姜 熟附子 猪胆汁 人尿
真武汤
白茯苓 白芍药 生姜 白术 熟附子
四逆汤
干姜 熟附子 炙甘草
通脉四逆汤
干姜 熟附子 炙甘草 葱白
葱白加于四逆汤中，则阳气和，血脉通；若腹痛，加白芍药，合戊己汤以和中，减去葱
Qin Zi said: The syndrome of Zhonghan (Cold Strike) is characterized by no fever in the body, coldness and reversal of the hands and feet, and clear, free urination and defecation. This is exactly what Zhang Zhongjing referred to as the True Yin Syndrome where pathogenic factors directly strike the Yin meridians. If there are aversion to cold and fever, it is a Yang syndrome of Shanghan (Cold Damage), not Zhonghan. Therefore, Zhang Zhongjing named cases with aversion to cold and fever as Shanghan, i.e., Yang syndrome; and cases with aversion to cold but no fever as Zhonghan, i.e., Yin syndrome. Now, I name the Yin syndrome where pathogenic factors directly strike the Yin meridians as Zhonghan; and the Yang syndrome where cold damages the Three Yang meridians as Shanghan, so that Yang syndromes are not confused within the categories of Yin syndromes.
[Symptoms of Zhonghan] Aversion to cold, curling up of the body, pain throughout the body, or spontaneous diarrhea, cold saliva in the mouth, face appearing as if scraped by a knife, coldness and reversal of the hands and feet, absence of fever with clear consciousness, non-chapped lips, no thirst, and clear white urine and stool. These are the symptoms of Zhonghan.
[Etiology of Zhonghan] The person's original True Yang has been deficient for a long time, and internal Yin-Cold is flourishing. The Yang Qi in the Stomach cannot defend the exterior; the Yang Qi in the Spleen cannot rot and ripen food in the middle jiao; the Yang Qi in the Kidney cannot seal and close the gates (secure the lower orifice). Once exposed to external cold, the pathogen directly strikes the Three Yin meridians, resulting in the syndrome of Zhonghan.
[Pulse of Zhonghan] The pulse is mostly deep and faint, or faint and slow, or extremely resembling cessation, or hidden and deep. It may also be empty and floating, or tight and wiry.
[Treatment of Zhonghan] When Cold strikes the Shaoyin meridian, and after two or three days, mild sweating should be induced, use Mahuang Fuzi Gancao Tang (Ephedra, Prepared Aconite, and Licorice Decoction). For Shaoyin syndrome with body pain, cold hands and feet, and a deep pulse, use Fuzi Tang (Aconite Decoction). If there is diarrhea with a faint pulse, use Baitong Tang (White Tongue-Scallion Decoction); if diarrhea persists, with cold reversal, absent pulse, dry heaving, and irritability, add Pig Bile to Baitong Tang to relieve irritability. For Shaoyin diarrhea accompanied by water qi, possibly with cough or vomiting, use Zhenwu Tang (True Warrior Decoction). For Taiyin spontaneous diarrhea without thirst, indicating cold in the zang organs, use Sini Tang (Frigid Extremities Decoction) to warm them. For Jueyin diarrhea with undigested food, pain in the four limbs, cold reversal, and aversion to cold, use Sini Tang. For Jueyin diarrhea with undigested food, sweating, and cold reversal, use Tongmai Sini Tang (Pulse-Resuscitating Frigid Extremities Decoction).
Mahuang Fuzi Gancao Tang (Ephedra, Prepared Aconite, and Licorice Decoction)
Ingredients: Ephedrae Herba (Mahuang, 麻黄), Preparata Radix Aconiti (Fuzi, 附子), Preparata Radix Glycyrrhizae (Gancao, 甘草)
Fuzi Tang (Aconite Decoction)
Ingredients: Preparata Radix Aconiti (Shu Fuzi, 熟附子), Atractodis Rhizoma (Baizhu, 白术), Poria (Baifuling, 白茯苓), Ginseng Radix et Rhizoma (Renshen, 人参), Paeoniae Radix Alba (Baishao, 白芍药)
Baitong Tang (White Tongue-Scallion Decoction)
Ingredients: Allii Fistulosi Bulbus (Congbai, 葱白), Zingiberis Rhizoma Recens (Ganjiang, 干姜), Preparata Radix Aconiti (Shu Fuzi, 熟附子)
Baitong Zhu Dan Tang (White Tongue-Scallion and Pig Bile Decoction)
Ingredients: Allii Fistulosi Bulbus (Congbai, 葱白), Zingiberis Rhizoma Recens (Ganjiang, 干姜), Preparata Radix Aconiti (Shu Fuzi, 熟附子), Porcis Bile (Zhudanshi, 猪胆汁), Hominis Urina (Reniao, 人尿)
Zhenwu Tang (True Warrior Decoction)
Ingredients: Poria (Baifuling, 白茯苓), Paeoniae Radix Alba (Baishao, 白芍药), Zingiberis Rhizoma Recens (Shengjiang, 生姜), Atractodis Rhizoma (Baizhu, 白术), Preparata Radix Aconiti (Shu Fuzi, 熟附子)
Sini Tang (Frigid Extremities Decoction)
Ingredients: Zingiberis Rhizoma Recens (Ganjiang, 干姜), Preparata Radix Aconiti (Shu Fuzi, 熟附子), Preparata Radix Glycyrrhizae (Zhigancao, 炙甘草)
Tongmai Sini Tang (Pulse-Resuscitating Frigid Extremities Decoction)
Ingredients: Zingiberis Rhizoma Recens (Ganjiang, 干姜), Preparata Radix Aconiti (Shu Fuzi, 熟附子), Preparata Radix Glycyrrhizae (Zhigancao, 炙甘草), Allii Fistulosi Bulbus (Congbai, 葱白)
Adding Congbai (Allii Fistulosi Bulbus) to Sini Tang harmonizes the Yang Qi and unblocks the blood vessels; if abdominal pain occurs, add Baishao (Paeoniae Radix Alba) and combine with Wuji Tang (Five Earths Decoction) to harmonize the middle jiao, removing Congbai.