治疗贵方药合宜，方药在气味合用。先圣设绳墨而取曲直，后哲出规矩以为方圆。
然物之生也必要乎天，其成也必资乎地，故有形为味，无形为气，气为阳，味为阴，阳
气出上窍，阴味出下窍，气化则精生、味化则形长，故地产养形，形不足者温之以气，
天产养精，精不足者补之以味，是以气者天也。气有四，温热者天之阳，寒凉者天之
阴。阳则升，阴则降。味者地也，味有六，辛甘淡者地之阳，酸苦寒者地之阴，阳则
浮，阴则沉。有使气者，有使味者，有气味俱使者，有先使气后使味者，有先使味后使
气者，更有因象而使，因色而使，因意而使者，不可一例而拘。有一药二味或三味者，
有一药一气或二气看，热者多，寒者少，寒不为之寒；寒者多，热者少，热不为之热。
或寒热各半而成温，或温多而成热，或凉多而成寒，不可一途而取。又或寒热各半，昼
服之，则从热之属而升∶夜服之，则从寒之属而降。至于晴日则从热，阴雨则从寒，所
从求类，变化不一也。然酸咸无升，甘辛无降，寒无浮，热无沉，其性然也。而升而使
之降，须其抑也；沉而使之浮，须其载也。辛散也，其行之也横；甘缓也，其行之也
上；苦泻也，其行之也下；酸收也，其性缩；咸软也，其性舒，上下舒缩横之不同又
如此。若夫热药之性，其伤人也必僭，以火曰炎上也。寒药之性，其伤人也必滥，以水
曰润下也。不僭不滥，而独伤中焦冲和之气者，必无之理也。
治疗的关键在于方药适宜，而方药的适宜取决于气味配合得当。先圣设立准绳来衡量事物的曲直，后哲制定规矩来界定事物的方圆。
然而，万物的生长必然依赖天时，其成熟必然借助地利。因此，有形的物质属于“味”，无形的能量属于“气”；气属于阳，味属于阴。阳气出于上窍（如口鼻），阴味出于下窍（如前后二阴）。气化则精气生成，味化则形体增长。所以，地产之物滋养形体，形体不足者用气来温补；天产之物滋养精气，精气不足者用味来滋补。因此，气归属于天。气分为四种：温热属于天的阳，寒凉属于天的阴。阳的特性是上升，阴的特性是下降。味归属于地，味分为六种：辛、甘、淡属于地的阳，酸、苦、寒属于地的阴。阳的特性是浮散，阴的特性是沉降。
用药时有使用气的，有使用味的，有气味共同使用的，有先用气后用味的，也有先用味后用的。更有因药物象数而选用、因颜色而选用、因意念而选用的，不能拘泥于一种模式。有一种药具备两种或三种味道，有一种药具备一种或两种气性。热性药多，寒性药少，整体就不显寒性；寒性药多，热性药少，整体就不显热性。或者寒热各半而成温性，或者温性多而成热性，或者凉性多而成寒性，不能只从一条途径去选取。又或者寒热各半，白天服用，则随热性一类而上行；夜晚服用，则随寒性一类而下沉。至于晴天则随热性，阴雨天气则随寒性，所遵循的类别不同，变化也就多种多样。
然而，酸味和咸味没有升提作用，甘味和辛味没有下降作用，寒性没有上浮特性，热性没有下沉特性，这是它们的本性使然。如果要让上升的药产生下降的作用，必须加以抑制；如果要让沉降的药产生上浮的作用，必须加以承载。辛味具有发散作用，其运行方向是横向的；甘味具有缓急作用，其运行方向是向上的；苦味具有泻下作用，其运行方向是向下的；酸味具有收敛作用，其性质是收缩的；咸味具有软坚作用，其性质是舒展的。上下、舒缩、横行的不同又如此这般。
至于热性药物的药性，伤害人体时必定表现为亢盛僭越，因为火的特性是炎上。寒性药物的药性，伤害人体时必定表现为泛滥无制，因为水的特性是润下。如果不出现亢盛僭越，也不出现泛滥无制，却唯独伤害中焦冲和之气，那是一定没有的道理。
The key to treatment lies in the appropriateness of the prescription and medicine, which depends on the proper combination of Qi (Vital Energy) and Flavor. The Ancient Sages established plumb lines and squares to measure straightness and crookedness, while later philosophers created compasses and set-squares to define circles and squares.
However, the generation of all things necessarily relies on Heaven (Time/Cosmic influences), and their maturation necessarily depends on Earth (Material/Substance). Therefore, what has form belongs to Flavor, and what is formless belongs to Qi. Qi is Yang, and Flavor is Yin. Yang Qi exits through the upper orifices (such as the mouth and nose), while Yin Flavor exits through the lower orifices (the urethra and anus). When Qi transforms, Essence (Jing) is generated; when Flavor transforms, Form (Xing) grows. Thus, products of the Earth nourish Form; for those with deficient Form, tonification should be done with Qi. Products of Heaven nourish Essence; for those with deficient Essence, tonification should be done with Flavor. Hence, Qi belongs to Heaven. There are four types of Qi: Warm and Hot belong to the Yang of Heaven, while Cold and Cool belong to the Yin of Heaven. Yang ascends, and Yin descends. Flavor belongs to Earth. There are six types of Flavor: Pungent, Sweet, and Bland belong to the Yang of Earth, while Sour, Bitter, and Cold belong to the Yin of Earth. Yang floats, and Yin sinks.
In prescribing, one may use Qi alone, Flavor alone, both Qi and Flavor together, first Qi then Flavor, or first Flavor then Qi. Furthermore, selection may be based on image/symbolism, color, or intent, so one cannot rigidly adhere to a single method. A single herb may possess two or three flavors, or one or two Qi properties. If there are many Heat-natured herbs and few Cold-natured ones, the overall nature will not be Cold; if there are many Cold-natured herbs and few Heat-natured ones, the overall nature will not be Heat. Two parts Cold and one part Heat may result in a Warm nature; more Warm than Heat results in a Hot nature; more Cool than Cold results in a Cold nature. One cannot rely on a single pathway for selection. Additionally, if a mixture is half Cold and half Heat, taking it during the day causes it to ascend following the Heat category; taking it at night causes it to descend following the Cold category. On sunny days, it follows Heat; on rainy or cloudy days, it follows Cold. Because the categories followed vary, the changes are diverse.
However, Sour and Salty flavors do not have ascending properties, while Pungent and Sweet flavors do not have descending properties. Cold substances do not float, and Hot substances do not sink; this is their inherent nature. To make an ascending agent descend, it must be restrained; to make a sinking agent float, it must be carried. Pungent disperses, and its movement is horizontal; Sweet moderates, and its movement is upward; Bitter drains, and its movement is downward; Sour astringes, and its nature is contracting; Salty softens hardness, and its nature is relaxing. The differences in vertical (up/down), expansion/contraction, and horizontal movement are thus manifested.
Regarding the nature of Heat medicines, when they damage the human body, they inevitably cause hyperactivity and usurpation (excessive rising), because Fire's nature is to blaze upward. Regarding the nature of Cold medicines, when they damage the human body, they inevitably cause flooding and overflow, because Water's nature is to moisten and flow downward. It is logically impossible for a substance to avoid both hyperactivity/usurpation and flooding/overflow, yet exclusively damage the Harmonious Qi (Chonghe Zhi Qi) of the Middle Jiao.