痰之见病甚多。痰之立治不少。如痰之在于经者宜散宜升。痰之在于上者宜涌宜吐。
痰之
在中在膈。不能以散不能以吐者。宜降宜下。此降之法所由起也。第降有在于肺以为治者。
如栝蒌贝母生白果杏仁土贝母诃子之属是也。有在胸膈以为治者。如硼砂礞石儿茶之属是也
。有在心肝以为治者。如牛黄之属是也。有在肝胆以为治者。如全蝎鹤虱之属是也。有在皮
里膜外以为治者。如竹沥之属是也。有在脾以为治者。如密陀僧白矾之属是也。有在肾以为
治者。如沉香海石之属是也。但贝母则合心肝以为治。射干则合心脾以为理。皆属清火清热
。降气下行。惟白矾则收逐热涎。或从上涌。或自下泄。各随其便。至于痰非热成。宜温宜
燥。宜收宜引。则又在人随症活泼。毋自拘也。
（蔓草）
栝蒌仁（专入肺。兼入脾胃）。气味甘寒。（成无己乃谓味苦。其说甚非。）功专降火
下气坠痰
。缘肺受火逼。则水必停而痰生。痰生则肺失养而气壅。故有喘急胸满。咳嗽咽闭口渴之病
矣。栝蒌性寒。味甘寒。能除上焦伤寒。胸膈郁结痰气。使之入肠胃而下降。（震亨曰。栝
蒌实治胸痹者。以其味甘性润。甘能补肺。润能降气。胸中有痰者。乃肺受火逼。失其降下
之令。今得甘缓润下之助。则痰自降。宜其为治嗽之要药也。且又能洗涤胸膈中垢腻郁热。
为治消渴之神药。）故仲景小陷胸汤。用此以治邪结在胸。又以小柴胡汤。用此易半夏以治
少阳症见口渴等症。然大要取其有清降之力。故能使之下行也。若谓此能补气。正未必然。
虚寒泻利者忌。（热利最宜。取其以寒降火。）实圆长如熟柿。子扁多脂。去油用。枸杞为使
。畏牛膝干漆。恶干姜。反乌头。
痰邪引发的病症非常多。治疗痰病的方法也不少。例如，痰邪停留在经络中的，适宜用发散、升提的方法；痰邪停留在上部的，适宜用涌吐的方法。
痰邪停留在中部或膈间，无法通过发散或涌吐来治疗的，适宜用降逆、攻下的方法。这就是“降法”产生的原因。然而，降法的应用需根据病变部位不同而有所区别：
有的针对肺部进行治疗，如瓜蒌、贝母、生白果、杏仁、土贝母、诃子这类药物；
有的针对胸膈进行治疗，如硼砂、礞石、儿茶这类药物；
有的针对心肝进行治疗，如牛黄这类药物；
有的针对肝胆进行治疗，如全蝎、鹤虱这类药物；
有的针对皮里膜外（指皮下与脏腑之间的空隙）进行治疗，如竹沥这类药物；
有的针对脾脏进行治疗，如密陀僧、白矾这类药物；
有的针对肾脏进行治疗，如沉香、海浮石这类药物。
但是，贝母能兼顾心肝两脏进行治疗，射干能兼顾心脾两脏进行调理，它们都属于清火清热、使气机下降的药物。只有白矾能收敛并驱逐热性涎沫，或者使其从上部涌出，或者使其从下部排泄，各随其便利。至于痰并非由热邪形成，而是适宜温燥、收敛、引纳的情况，则又需要根据症状灵活处理，不要自我拘泥。
（蔓草注）
瓜蒌仁（专门入肺经，兼入脾胃经）。气味甘寒。（成无己认为味苦，这种说法非常错误。）功效专门在于降火、下气、坠痰。因为肺受到火邪逼迫，津液必然停滞而生痰。痰生成后，肺失去滋养而导致气机壅滞，所以会出现喘急、胸闷、咳嗽、咽喉闭塞、口渴等病症。瓜蒌性寒，味甘寒，能够清除上焦的伤寒郁结和胸膈间的痰气，使其进入肠胃而向下排出。（朱震亨说：瓜蒌实治疗胸痹，是因为它味甘性润，甘能补肺，润能降气。胸中有痰，是肺受火邪逼迫，失去了降下的功能。现在得到甘缓润下的帮助，痰自然下降，所以它是治疗咳嗽的重要药物。而且它能洗涤胸膈中的污垢腻滞和郁热，是治疗消渴的神药。）因此，张仲景在小陷胸汤中使用它来治疗邪气结聚在胸部的病症；又在小柴胡汤中，用它代替半夏来治疗少阳症出现口渴等症状。但大要之旨在于它具有清降的力量，所以能使痰下行。如果说它能补气，那未必确实。虚寒泄泻者忌用。（热性泄泻最适宜，因为它能寒降火邪。）果实形状像熟透的柿子一样圆长，种子扁平且多油脂，需去油使用。枸杞为引经药。畏牛膝、干漆。恶干姜。反乌头。
The manifestations of phlegm are numerous. The treatments for phlegm are also many. For instance, when phlegm resides in the meridians (Meridians, the pathways through which Qi and blood flow), it is suitable to disperse and elevate it. When phlegm resides in the upper part of the body, it is suitable to induce vomiting.
When phlegm resides in the middle or at the diaphragm, and cannot be treated by dispersion or vomiting, it is suitable to descend and purge it. This is how the method of descending was originated. However, the application of descending methods varies according to the affected organ:
Some target the Lung for treatment, such as Trichosanthis Fructus (Gualou), Fritillariae Bulbus (Beimu), raw Ginkgo Seed (Baiguo), Armeniacae Semen (Xingren), Smilacis Rhizoma (Tubeimu), and Terminalia Chebula Retz. (Hezi);
Some target the chest and diaphragm for treatment, such as Borax (Pengsha), Pyritum (Mengshi), and Myrrha (Ercha);
Some target the Heart and Liver for treatment, such as Calculus Bovis (Niuhuang);
Some target the Liver and Gallbladder for treatment, such as Scorpio (Quanxie) and Pyrethri Flos (Heshi);
Some target the area between the skin and membranes (the space between subcutaneous tissue and organs) for treatment, such as Bamboo Sap (Zhuli);
Some target the Spleen for treatment, such as Colcothar (Mituo seng) and Alum (Bai fan);
Some target the Kidney for treatment, such as Aquilariae Lignum Resinatum (Chenxiang) and Lapillus (Haishi).
However, Fritillariae Bulbus (Beimu) treats both the Heart and Liver, and Belamcandae Rhizoma (Shegan) regulates both the Heart and Spleen; both belong to herbs that clear fire and heat, and direct Qi downward. Only Alum (Bai fan) can astringe and expel hot saliva, either inducing vomiting from above or purging from below, depending on convenience. As for phlegm not formed by heat, which requires warming, drying, astringing, or guiding, one must act flexibly according to symptoms and not be rigidly bound by rules.
(Note by Mancao)
Trichosanthis Semen (Gualou Ren) (Specifically enters the Lung meridian, and concurrently enters the Spleen and Stomach meridians). Its flavor and nature are sweet and cold. (Cheng Wuji claimed it was bitter, which is a very incorrect view.) Its function is specifically to descend fire, lower Qi, and drop phlegm. Because the Lung is pressured by fire, fluids inevitably stagnate and generate phlegm. Once phlegm is generated, the Lung loses nourishment and Qi becomes obstructed, leading to conditions such as panting, chest fullness, cough, throat closure, and thirst. Trichosanthis is cold in nature and sweet in flavor; it can eliminate cold-induced stagnation in the Upper Jiao and resolve phlegm-Qi accumulation in the chest and diaphragm, causing them to enter the intestines and stomach and descend. (Zhu Zhenheng stated: Trichosanthis Fructus treats Chest Bi [Chest Obstruction] because its sweet flavor and moistening nature benefit the Lung and direct Qi downward. Phlegm in the chest results from the Lung losing its descending function due to fire pressure. With the assistance of sweet,緩缓, and moistening descent, phlegm naturally descends, making it an essential herb for treating coughs. Furthermore, it can cleanse foulness, greasiness, and stagnant heat in the chest and diaphragm, making it a divine herb for treating Xiao Ke [Wasting-Thirst].) Therefore, Zhang Zhongjing used this herb in Xiao Xian Xiong Tang (Minor Intra-Chest Decoction) to treat evil pathogens knotted in the chest, and in Xiao Chai Hu Tang (Minor Bupleurum Decoction), he replaced Ban Xia with this herb to treat Shaoyang syndrome presenting with thirst, among other symptoms. The main point is that it possesses the power of clearing and descending, thus enabling downward movement. To claim it tonifies Qi is not necessarily true. It is contraindicated for deficiency-cold diarrhea. (It is most suitable for heat-type diarrhea, taking advantage of its cold nature to descend fire.) The fruit is round and long like a ripe persimmon; the seeds are flat and rich in oil, which should be removed before use. Lycii Fructus (Gouqi) serves as a guide drug. It is incompatible with Achyranthis Bidentatae Radix (Niuxi) and Dried Lacca (Ganqi). It opposes Zingiberis Rhizoma Recens (Ganjiang). It is antagonistic to Aconiti Lateralis Radix Praeparata (Wutou).