凡治痢疾，用白芍、槟榔、木香、黄连者，此数药皆味极苦涩，性极沉降者也。因痢疾
是湿热
邪毒，旁渍肠胃细络夹膜之中，苦涩之味能吸而出之，随渣滓而俱下矣。故里急后重用此等
药，攻下秽涎而病愈者，肠胃络膜之浊气泄尽也。若用大黄、芒硝，伤正留邪，每至不救；
若用粟壳、乌梅，固脱留邪，多成休息，得其一而遗其一也。钱仲阳治小儿惊痫，轻粉、巴
豆牵牛并用，一敛一泄，即摄取痰涎而驱下之也。古方此类甚多。
凡欲发汗，须养汗源，非但虑其伤阴，亦以津液不充，则邪无所载，仍不得出也。故桂
枝汤
中用芍药，或更加黄芩；麻黄汤中用杏仁，或更加石膏∶匪但意清内热，以为胃汁充盈，邪
乃有所附而聚，聚乃可驱之使尽耳!故《伤寒论》有发热自汗而病不愈，以桂枝汤先其时发
汗则愈者，充其荣，则卫不能藏奸也。张石顽曰∶凡患温热，烦渴不解，往往得水，或服黄
芩、石膏等寒药，浃然汗出而解者，肠胃燥热，力不胜邪，寒清助胃生津故也。凡辛散之剂
，佐用甘酸，皆此义也。小青龙之五味子，大青龙之石膏，桂枝汤之白芍，最可玩味。
桂枝是温通血脉之为寒闭者。吐血病中，有一种肾寒而元阳虚者，胃寒而中气怯者，皆
令血
脉不能通畅，遂旁溢而妄行。《内经》所谓血泄者，是脉急血无所行也。其证得节即动，迟
速有定期。如妇人月信者，脉既不畅，血盈即倾之而出也。每以桂枝为君治之，应手辄效，
章虚谷亦盛称桂枝能通血脉之寒闭也。若咳嗽见血，不因吐出者，尤属寒闭无疑。而世人每
谓桂能动血，一见血证，辄循例概禁用桂。误哉!
凡是治疗痢疾，使用白芍、槟榔、木香、黄连这几味药的，是因为这几味药味道极苦涩，药性极沉降。因为痢疾是湿热邪毒，浸渍在肠胃细微络脉和夹膜之间，苦涩的味道能够将其吸附出来，随着糟粕一起排出体外。所以里急后重时重用这类药物，攻下秽浊涎沫而病愈的，是因为肠胃络膜的浊气排尽了。如果使用大黄、芒硝，会损伤正气而留滞邪气，往往导致无法救治；如果使用罂粟壳、乌梅，固涩止脱而留滞邪气，多变成休息痢（迁延不愈的痢疾），顾此失彼。钱乙治疗小儿惊痫，轻粉、巴豆、牵牛子并用，一敛一泄，即摄取痰涎并驱除下去。古方中这类情况很多。
凡是想要发汗，必须滋养汗源，不仅担心其伤阴，也因为津液不充足，则邪气没有载体，仍然不能排出。所以桂枝汤中使用芍药，或者再加黄芩；麻黄汤中使用杏仁，或者再加石膏：不仅仅是为了清除内热，为了让胃汁充盈，邪气才有依附聚集之处，聚集了才能将其驱除干净！所以《伤寒论》中有发热自汗但病不愈的情况，在适当时候用桂枝汤发汗就能痊愈，这是因为充养了营气，卫气就不能藏匿奸邪。张璐说：凡是患温热病，烦渴不解，往往喝水，或者服用黄芩、石膏等寒凉药物，大汗出而病解的，是因为肠胃燥热，力量不足以抗邪，寒凉清润帮助胃生津液所致。凡是辛散的药物，辅助使用甘酸之品，都是这个道理。小青龙汤中的五味子，大青龙汤中的石膏，桂枝汤中的白芍，最值得玩味体会。
桂枝是用来温通血脉，针对被寒邪闭阻的情况。吐血病中，有一种是肾寒而元阳虚，胃寒而中气怯弱的，都会导致血脉不能通畅，于是血液旁溢而妄行。《内经》所说的“血泄”，就是脉管拘急，血无所行。这种病症发作有定时，快慢有规律。如妇女月经来潮，脉道既不畅，血液充盈就倾泻而出。常常以桂枝为君药治疗，应手见效，章楠也极力称赞桂枝能通血脉之寒闭。如果是咳嗽见血，不是吐出来的，尤其属于寒闭无疑。然而世人常说桂枝动血，一见血证，就按惯例一概禁用桂枝。这是错误的！
In the treatment of dysentery, when Baishao (Radix Paeoniae Alba), Binglang (Arecae Semen), Muxiang (Aucklandiae Radix), and Huanglian (Coptidis Rhizoma) are used, it is because these herbs possess extremely bitter and astringent flavors and have a strongly descending nature. Dysentery is caused by damp-heat pathogenic factors and toxins infiltrating the fine collaterals and mesenteric membranes of the intestines and stomach. The bitter and astringent flavors can absorb these pathogens, which then descend along with the fecal matter. Therefore, in cases of tenesmus (里急后重), heavy use of such drugs expels turbid saliva and pathogens, leading to recovery as the turbid qi in the intestinal and gastric collaterals and membranes is exhausted. If Dahuang (Rhei Radix et Rhizoma) and Mangxiao (Natrii Sulfas) are used, they damage healthy qi while retaining pathogens, often resulting in untreatable conditions; if Yingkesu (Papaveris Pericarpium) and Wumei (Mume Fructus) are used, they consolidate and stop leakage but retain pathogens, frequently leading to chronic dysentery (Xixie), where one aspect is addressed while the other is neglected. Qian Yiyuan treated pediatric convulsive epilepsy using Qingfen (Calomel), Badou (Crotonis Fructus), and Qianniu (Pharbitidis Semen) together, employing one method to astringe and another to purge, thereby capturing phlegm-saliva and driving it downward. There are many such ancient prescriptions.
To induce sweating, one must nourish the source of sweat. This is not only to prevent injury to yin, but also because if body fluids are insufficient, there is no carrier for the pathogen, making expulsion impossible. Thus, in Guizhi Tang (Cinnamon Twig Decoction), Shaoyao (Radix Paeoniae Alba) is used, or Huangqin (Scutellariae Radix) is added; in Mahuang Tang (Ephedra Decoction), Xingren (Armeniacae Semen Amarum) is used, or Shigao (Gypsum Fibrosum) is added: this is not merely to clear internal heat, but to ensure sufficient gastric juices so that pathogens have a basis to gather; once gathered, they can be completely expelled. Hence, in *Shanghan Lun* (Treatise on Cold Damage), cases of fever with spontaneous sweating that do not resolve are cured by administering Guizhi Tang at the appropriate time to induce sweating; by replenishing Ying (Nutritive Qi), Wei (Defensive Qi) cannot harbor pathogens. Zhang Lu stated: In warm-heat diseases, when restlessness and thirst persist, drinking water or taking cold herbs like Huangqin or Shigao often leads to resolution through profuse sweating. This occurs because dry-heat in the intestines and stomach lacks the strength to overcome the pathogen; the cold and clearing properties help generate stomach fluids. For all acrid-dispersing agents, assisting them with sweet and sour substances follows this principle. The Wuweizi (Schisandrae Fructus) in Xiao Qinglong Tang (Minor Blue Dragon Decoction), Shigao in Da Qinglong Tang (Major Blue Dragon Decoction), and Baishao in Guizhi Tang are most worthy of careful study.
Guizhi (Cinnamomi Ramulus) is used to warm and unblock blood vessels obstructed by cold. In hematemesis (vomiting blood), there is a type caused by kidney cold and deficiency of primal yang, or stomach cold and weakness of middle qi, both of which prevent smooth blood flow, causing blood to overflow and act recklessly. As stated in *Neijing* (The Inner Canon), "blood leakage" refers to vessel constriction where blood has nowhere to go. Such symptoms occur at regular intervals with predictable timing. For example, in women's menstruation, when the pulse is unsmooth, blood accumulates until it is discharged. Treating this primarily with Guizhi often yields immediate results. Zhang Xu also highly praised Guizhi for its ability to unblock cold obstruction in blood vessels. If coughing up blood without vomiting, it is undoubtedly due to cold obstruction. However, people generally claim that Guizhi moves blood, and upon seeing any blood disorder, they routinely prohibit its use. This is a mistake!