（许学士退阴与正元同煎，以治阴证咳逆）
夫逆病咳逆，火炎上使阴气不内也。阴气者，即吸入之阴气也。阴证内寒，与吸入之阴
同类
逆者，胃热失下也。阴气先绝，阳气后亦将竭，火独炎上，逆出阴气而为咳逆也。阴证者，
内已伏阴，阴气太甚，肾水擅权，肝气不生，胃火已病，丁火又消，所有游行相火，寒邪迫
而萃集于胸中，亦欲尽也。故令人发躁，大渴引饮，并去盖覆，病患独觉热，他人按执之，
身体肌肉骨髓血脉皆寒。此火即无根之火也，故用丁香、干姜之类热药温胃，其火自下，咳
逆方止。非若凉膈、泻心，以治阳证，自上而下，泻退其火，阴气乃生。阴证咳逆，从呕哕
而生，胃寒呕哕不已，咳逆继之，其声怏怅连续不已，声末而作咳逆，古人云烦冤是也。烦
冤者，有情不能诉，有怀不能吐，故为怏怅，唯阴证阳脱而咳逆者，其状似之。阳证咳逆，
内热与上热相接，咳逆止在喉中；阴证咳逆，呕从内出，或先作去声，或与去声相并而至喉
中，故用温胃益肺之药主之。中既温，天五之气与残火自下，又与胃中温药相接，变而阳气
生也。殆无异丧家之人，遑遑无根据，契昔挽留，故都是反与相并立而干成其事，阴气始退，
阳气渐生，脉亦从之而得以获生也。
《灵苑》治阴咳逆，匀气散
川乌头（尖者三个，炮制，去皮脐）
上为细末，每服二钱，黑豆二十一粒，糖沙鸡头入大水一盏，同煎至六分，承热细细饮之。
《本事》治阴毒吃逆。
川乌头 干姜 附子（俱炮） 肉桂 芍药 甘草（炙） 半夏 吴茱萸 陈皮 大黄
上各等分，为末。每服一钱，水一盏，生姜三五片，煎至七分，去浊滓取清，热呷。
(Physician Xu boiled Tuiyin San (Decoction for Driving Out Yin) and Zhengyuan San (Decoction for Supporting the Primordial Qi) together to treat coughing and upward reversal of qi caused by Yin syndrome.)
The condition known as "reversal" involving coughing and upward reversal of qi is caused by fire blazing upwards, preventing Yin qi from remaining within. The so-called Yin qi refers to the clear qi inhaled into the body (which belongs to Yin). Yin syndrome manifests as internal cold, which shares the same nature as the inhaled Yin qi.
Here, "reversal" refers to heat in the Stomach that has not been expelled through purgation. At this stage, Yin qi has first exhausted itself, and Yang qi will soon follow; only fire blazes alone upwards. The rebellious qi emerges from the state of depleted Yin qi, resulting in coughing and upward reversal of qi.
The essence of Yin syndrome is the latent presence of Yin-cold within the body. Yin qi is excessively strong, Kidney Water dominates unchecked, Liver Wood fails to generate, Stomach Fire is already damaged, and Heart Fire (Ding Fire) also diminishes. The Ministerial Fire (Xiang Huo) that normally circulates is forced by Cold pathogens to gather in the chest and is also on the verge of extinction. Consequently, the patient experiences restlessness, extreme thirst with a desire to drink, and a tendency to remove covers. Although the patient feels hot internally, palpation of the body, muscles, bones, marrow, and blood vessels by others reveals coldness. This fire is rootless fire; therefore, warming herbs such as Ding Xiang (Clove) and Gan Jiang (Dried Ginger) are used to warm the Stomach. When the fire naturally descends, the coughing and upward reversal of qi cease. This differs from the treatment of Yang syndrome using Liang Ge San (Cooling the Chest Decoction) or Xie Xin Tang (Drain the Epigastrium Decoction), where fire is cleared from above downwards, allowing Yin qi to regenerate.
Coughing and upward reversal of qi in Yin syndrome often originate from vomiting and hiccups. If vomiting and hiccups due to Stomach Cold persist, coughing and upward reversal of qi will follow. The sound is mournful and continuous, triggering coughing at the end of each exhalation. The ancients termed this state "Fan Yuan" (Distress and Grievance). "Fan Yuan" describes a feeling of having emotions that cannot be expressed and grievances that cannot be voiced, leading to a sense of depression and discomfort. Only the coughing and upward reversal of qi caused by the collapse of Yang qi in Yin syndrome resembles this presentation.
In Yang syndrome, internal heat connects with upper heat, and the coughing/reversal sensation remains confined to the throat. In Yin syndrome, the vomit/qi originates from within; it may first produce an expulsive sound ("qu sheng") or arrive at the throat simultaneously with this sound. Therefore, the primary treatment involves herbs that warm the Stomach and benefit the Lungs. Once the interior is warmed, the Tian Wu Zhi Qi (Primordial Qi of Heaven and Five) and residual fire rise from below, merging with the warming herbs in the Stomach, thereby transforming and generating Yang qi. This is akin to a person who has lost their home, acting frantically without support; past attempts to retain them failed, so now they stand together to accomplish the matter. Only when Yin qi begins to recede and Yang qi gradually grows, and the pulse changes accordingly, can the patient survive.
*Ling Yuan* records Yunqi San (Harmonizing Qi Powder) for treating Yin coughing and upward reversal of qi:
Chuan Wu Tou (Aconiti Lateralis Radix Praeparata - select three pointed tubers, processed, skin and bud removed)
Grind the above into a fine powder. Take 2 qian per dose. Combine with 21 black soybeans, sugar sand, and Jiao Tou Mi (Sparganii Rhizoma), add one large cup of water, and decoct together until six-tenths of the liquid remains. Drink slowly while hot.
*Benshi Fang* records a formula for treating Yin toxicity hiccups:
Chuan Wu Tou (Aconiti Lateralis Radix Praeparata), Gan Jiang (Zingiberis Rhizoma Recens/Secatus), Fu Zi (Aconiti Lateralis Radix Praeparata), Rou Gui (Cinnamomi Cortex), Shao Yao (Paeoniae Radix Alba), Gan Cao (Glycyrrhizae Radix et Rhizoma - honey-fried), Ban Xia (Pinelliae Rhizoma), Wu Zhu Yu (Evodiae Fructus), Chen Pi (Citri Reticulatae Pericarpium), Da Huang (Rhei Radix et Rhizoma).
Take equal parts of each, grind into powder. Take 1 qian per dose. Add one cup of water and 3-5 slices of fresh ginger. Decoct until seven-tenths of the liquid remains. Filter out the dregs, take the clear liquid, and sip slowly while hot.