一寒方之制。为清火也。为除热也。夫火有阴阳。热分上下。据古方书。咸谓黄连清心。黄芩
清肺。石斛、芍药清脾。龙胆清肝。黄柏清肾。今之用者。多守此法。亦是胶柱法也。大凡寒凉之物。
皆能泻火。岂有凉此而不凉彼者。但当分其轻清重浊。性力微甚。用得其宜。则善矣。夫轻清者宜以清上。
如黄芩、石斛、连翘、天花粉之属也。重浊者宜于清下。如栀子、黄柏、龙胆、滑石之属也。性力
之浓者能清大热。如石膏、黄连、芦荟、苦参、山豆根之属也。性力之缓者能清微热。如地骨皮、玄参、
贝母、石斛、童便之属也。以攻而用者去实郁之热。如大黄、芒硝之属也。以利而用者去癃闭之热。
如木通、茵陈、猪苓、泽泻之属也。以补而用者去阴虚枯燥之热。如生地、二冬、芍药、梨浆、细甘草
之属也。方书之分经用药者。意正在此。但不能明言其意耳。然火之甚者在上。亦宜重浊。火之微者
在下。亦可轻清。夫宜凉之热。皆实热也。实热在下。自宜清利。实热在上。不可升提。盖火本属阳。
宜从阴治。从阴治者宜降。升则反从其阳矣。经曰。高者抑之。义可知也。外如东垣有升阳散火之法。
此以表邪生热者设。不得与伏火内炎者并论。（表邪生热。当作郁热外发为妥。）
制定寒凉方剂的宗旨，在于清除火邪、消除热证。火分阴火与阳火，热有上焦与下焦之别。根据古代医方书籍的记载，普遍认为黄连能清心火，黄芩能清肺热，石斛和芍药能清脾热，龙胆草能清肝火，黄柏能清肾火。如今使用这些药物的人，大多拘泥于这种固定方法，这也是一种不知变通的僵化做法。大凡寒凉性质的药物，都能泻火，难道会有只凉这一处而不凉那一处的道理吗？关键在于要区分药物的轻清与重浊之性，以及药力的微弱与强烈，运用得当，才是好的治疗方法。
那些性质轻清的药材，适宜用于清泄上部的热邪，如黄芩、石斛、连翘、天花粉这类药物。性质重浊的药材，适宜用于清泄下部的热邪，如栀子、黄柏、龙胆草、滑石这类药物。药力浓烈的，能够清除大热，如石膏、黄连、芦荟、苦参、山豆根这类药物。药力缓和的，能够清除微热，如地骨皮、玄参、贝母、石斛、童便（儿童尿液）这类药物。以攻逐法使用的，是为了去除实邪郁结的热，如大黄、芒硝这类药物。以利水法使用的，是为了去除小便癃闭不通的热，如木通、茵陈、猪苓、泽泻这类药物。以补益法使用的，是为了去除阴虚导致的枯燥之热，如生地黄、天冬与麦冬、芍药、梨浆、细甘草这类药物。医方书中按经络划分用药的方法，用意正在于此，只是没有明确说明其中的深意罢了。
然而，如果火邪严重且位于上部，也适宜使用重浊的药物；如果火邪轻微且位于下部，也可以使用轻清的药物。凡是适宜用寒凉药物治疗的热证，都属于实热。实热在下部，自然适宜采用清热利湿的方法；实热在上部，不可使用升提之法。因为火的本性属于阳，适宜从阴的角度来治疗。从阴治则宜降逆，如果升提反而顺应了火的阳性。《内经》说：“病位高的，要用抑制的方法。”这个道理就可以明白了。另外，李东垣有“升阳散火”的治疗方法，这是为了解除因表邪引起的发热而设立的，不能将其与伏火内炎的情况混为一谈。（注：原文括号内认为“表邪生热”改为“郁热外发”更为妥当。）
The formulation of cold-natured prescriptions aims to clear fire and eliminate heat. Fire is categorized into Yin fire and Yang fire, while heat is differentiated between the Upper Jiao (Upper Burner) and Lower Jiao (Lower Burner). According to ancient medical texts, it is generally believed that Huanglian (Coptidis Rhizoma) clears Heart fire, Huangqin (Scutellariae Radix) clears Lung heat, Shihu (Dendrobii Caulis) and Shaoyao (Paeoniae Radix) clear Spleen heat, Longdan (Gentianae Radix) clears Liver fire, and Huangbai (Phellodendri Cortex) clears Kidney fire. Practitioners today often adhere strictly to this method, which is a rigid approach lacking flexibility. In general, all cold-natured substances can purge fire; how could there be a substance that cools one area but not another? The key lies in distinguishing between light/clear (Qing) and heavy/turbid (Zhuo) properties, as well as the intensity of their efficacy. When applied appropriately, the treatment will be effective.
Substances with light and clear properties are suitable for clearing heat in the upper body, such as Huangqin (Scutellariae Radix), Shihu (Dendrobii Caulis), Lianqiao (Forsythiae Fructus), and Tianhuafen (Trichosanthis Radix). Substances with heavy and turbid properties are suitable for clearing heat in the lower body, such as Zhizi (Gardeniae Fructus), Huangbai (Phellodendri Cortex), Longdan (Gentianae Radix), and Huashi (Talcum). Those with potent efficacy can clear severe heat, such as Shigao (Gypsum Fibrosum), Huanglian (Coptidis Rhizoma), Lvhui (Aloe), Kushen (Sophorae Flavescentis Radix), and Shandougen (Sophorae Tonkinensis Radix). Those with mild efficacy can clear slight heat, such as Digupi (Lycii Cortex), Xuanshen (Scrophulariae Radix), Beimu (Fritillariae Cirrhosae Bulbus), Shihu (Dendrobii Caulis), and Tongbian (Urine of Children). Used for purging, they remove heat caused by excess stagnation, such as Dahuang (Rhei Radix et Rhizoma) and Mangxiao (Natrii Sulfas). Used for promoting urination, they remove heat associated with urinary retention, such as Mutong (Akebiae Caulis), Yichen (Artemisiae Scopariae Herba), Zhuling (Polyporus), and Zexie (Alismatis Rhizoma). Used for tonifying, they remove dryness-heat due to Yin deficiency, such as Shengdi (Rehmanniae Radix), Er Dong (Tian Dong - Asparagi Radix and Mai Dong - Ophiopogonis Radix), Shaoyao (Paeoniae Radix), Lijiang (Pear Juice), and Xigancao (Glycyrrhizae Radix et Rhizoma Praeparata cum Melle). The classification of herbs by meridian in medical texts intends precisely this, though the underlying rationale is not explicitly stated.
However, if fire is severe and located in the upper part, heavy and turbid herbs may also be appropriate; if fire is mild and located in the lower part, light and clear herbs may be used. Any heat suitable for cooling treatment is Excess Heat (Shi Re). If Excess Heat is in the lower part, clearing and draining methods are naturally appropriate. If Excess Heat is in the upper part, lifting methods should not be used. Since fire inherently belongs to Yang, it should be treated from the perspective of Yin. Treating from Yin implies descending; lifting would instead follow its Yang nature. The Classic states: "For those high above, suppress them." This principle is evident. Additionally, Li Dongyuan proposed the method of "Ascending Yang and Dispersing Fire," which was established for heat generated by exterior pathogens. It cannot be conflated with internal flaming of latent fire. (Note: "Heat generated by exterior pathogens" is more accurately described as "Stagnant heat erupting externally.")