麻黄（二两去节） 附子（一枚炮去皮破八片） 细辛（二两）
上三味。以水一斗。先煮麻黄减二升。去上沫。内诸药。煮取三升。去滓。温服一升。日三服。
成注引内经曰。寒淫于内。治以甘热。佐以苦辛。以辛润之。麻黄之甘。以解少阴之寒。附子细辛之辛。以温
少阴之经。
内台方议云。用附子为君。以温经散寒。细辛之辛。以散少阴之寒邪为臣。麻黄能取汗。用之为佐使。以此三
味之剂发汗。非少阴则不敢用也。
内台方疑问曰。阴证不得使有汗。今者少阴病反发热而汗之者。何也。答曰。少阴属肾为里。当无热。为有相
火之位。亦能发热。其脉虽沉细。必当取微汗而后已也。
琥按上方议。犹未明畅。愚以炮附子之辛热。用以温少阴之里。细辛之辛热。专以走少阴之经麻黄之辛甘热。
大能发表。三者相合。使里温而阳气不脱。表透而寒邪得散。尚论篇云。此少阴表法之正。良有以夫。
少阴病得之二三日。麻黄附子甘草汤。微发汗。以二三日无里证。故微发汗也。（此条病当承上条而言。上条
反发热脉沉。此亦反发热脉沉。但上言始得之为急。此言得之二三日为缓病势稍缓。治法亦缓。故用麻黄附子甘草
汤微发其汗。无里证者。为无吐利躁烦干呕厥逆等证也。故仍从微汗以温发之。）
麻黄（二两，去节） 附子（一枚，炮制后去皮，破成八片） 细辛（二两）
以上三味药。用水一斗。先煮麻黄，水量减少二升时，去掉水面上的浮沫。加入其余药物。继续煎煮至剩余三升药液。滤去药渣。每次温服一升。每日服用三次。
成无己的注释引用《内经》说：寒邪侵扰体内，治疗应用甘热性质的药物为主，辅以苦、辛性质的药物。用辛味药来润燥。麻黄的甘味，用来解除少阴经（足少阴肾经）的寒邪。附子和细辛的辛味，用来温通少阴经。
《内台方议》评论说：使用附子作为君药（主药），以温通经脉、驱散寒邪。细辛的辛味，用来驱散少阴经的寒邪，作为臣药（辅药）。麻黄能发汗，用作佐使药（引导药或辅助药）。以此三味药组成的方剂发汗，如果不是少阴病，是不敢使用的。
《内台方疑问》问道：阴证患者不应使用发汗法。现在少阴病反而出现发热症状却使用发汗法，为什么呢？回答是：少阴属肾，位于体内深层，本应无热。但因为少阴包含相火（寄居于肝肾之火）的位置，也能发热。其脉象虽然沉细，但必须采取微汗的方法治疗才能痊愈。
琥按语认为上述议论还不够明白流畅。我认为炮附子的辛热之性，用来温补少阴里的虚寒；细辛的辛热之性，专门通行于少阴经；麻黄的辛甘热之性，大能发散表邪。三者配合，使里气温暖而阳气不致脱失，表透达而寒邪得以消散。《尚论篇》说：这是治疗少阴病表证的正规方法，确实有道理。
少阴病发病二三天，使用麻黄附子甘草汤，轻微发汗。因为发病二三天没有里证（脏腑内部的严重病变），所以采用轻微发汗的方法。（这一条病情应当承接上一条来说。上一条是刚得病就反发热、脉沉，这一条也是反发热、脉沉。只是上一条说“始得之”属于急症，这一条说“得之二三日”属于缓症，病势稍缓，治疗方法也较缓和，所以用麻黄附子甘草汤轻微发汗。所谓“无里证”，是指没有呕吐、腹泻、烦躁、干呕、四肢厥逆等症状。因此仍然从轻微发汗的角度，用温性的方法发散邪气。）
Ephedrae Herba (Mahuang, 麻黄) (two liang, remove nodes)
Aconiti Lateralis Radix Praeparata (Fuzi, 附子) (one piece, processed, peel removed, broken into eight pieces)
Xanthanae Radix (Xixin, 细辛) (two liang)
Take the above three herbs. Use one dou of water. First decoct Ephedrae Herba until the volume decreases by two sheng. Remove the foam on the surface. Add the remaining herbs. Continue to decoct until three sheng of liquid remain. Strain off the dregs. Take one sheng warm. Administer three times a day.
Cheng Wuji's commentary cites the *Neijing* (Inner Canon): When cold pathogen invades the interior, treat with sweet and hot substances, assist with bitter and pungent substances. Use pungent substances to moisten. The sweetness of Mahuang resolves the cold of Shaoyin (Lesser Yin). The pungency of Fuzi and Xixin warms the Shaoyin meridians.
The *Neitai Fangyi* comments: Use Fuzi as the sovereign drug (Jun) to warm the meridians and dissipate cold. The pungency of Xixin dissipates the cold pathogen in the Shaoyin meridian, serving as the minister drug (Chen). Mahuang induces sweating and serves as the assistant and envoy drug (Zuo-Shi). This formula inducing sweat should not be used unless it is a Shaoyin disease.
The *Neitai Fangyiwen* asks: Yin syndromes should not use diaphoresis. Now, why does Shaoyin disease present with fever and yet use diaphoresis? The answer is: Shaoyin belongs to the Kidney and is deep within; it should normally have no fever. However, since it contains the location of Ministerial Fire (Xianghuo), it can also produce fever. Although the pulse is deep and fine, treatment must achieve slight sweating to resolve the condition.
Hu's note states that the above discussions are not entirely clear. I believe the pungent-heat nature of processed Fuzi warms the interior of Shaoyin; the pungent-heat nature of Xixin specifically travels through the Shaoyin meridians; the pungent-sweet-heat nature of Mahuang greatly releases the exterior. The combination of these three warms the interior so Yang Qi does not collapse, and opens the exterior so Cold Pathogen is dispersed. The *Shanglun Pian* states: This is the correct method for treating the exterior aspect of Shaoyin disease; this is indeed reasonable.
When Shaoyin disease occurs for two or three days, use Mahuang Fuzi Gancao Tang to induce slight sweating. Because there are no interior syndromes after two or three days, slight sweating is employed. (This clause follows the previous one. The previous clause presented with immediate fever and deep pulse; this one also presents with fever and deep pulse. However, the previous one described an acute onset ("just acquired"), while this one describes a slower progression ("acquired two or three days ago"). The pathogenic trend is slightly milder, so the treatment is gentler, using Mahuang Fuzi Gancao Tang for slight sweating. "No interior syndrome" means there are no symptoms such as vomiting, diarrhea, restlessness, dry heaving, or cold extremities. Therefore, we still proceed with gentle sweating using warming methods.)