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。
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).