《阴阳应象论》曰∶积阳为天，积阴为地。阴静阳躁，阳生阴长，阳杀阴藏。
阳化气，阴成形。阳为气，阴为味。味归形，形归气，气归精，精归化，精食气，形食
味，化生精，气生形。味伤形，气伤精，精化为气，气伤于味。阴味出下窍，阳气出上窍。
清阳发腠理，浊阴走五脏；清阳实四肢，浊阴归六腑。味浓者为阴，薄者为阴中之阳；气浓
者为阳，薄者为阳中之阴。味浓则泄，薄则通；气薄则发泄，浓则发热。辛甘发散为阳，酸
苦涌泄为阴；咸味涌泄为阴，淡味渗泄为阳。六者或收或散，或缓或急，或润或燥，或软或
坚，以所利而行之，调其气，使之平也。
元素曰∶清之清者，发腠理；清之浊者，实四肢。浊之浊者，归六腑；浊之清者，走五
脏。附子气浓，为阳中之阳；大黄味浓，为阴中之阴。茯苓气薄，为阳中之阴，所以利小便，
入手太阳，不离阳之体也；麻黄味薄，为阴中之阳，所以发汗，入手太阴，不离阴之体也。
凡同气之物必有诸味，同味之物必有诸气。气味各有浓薄，故性用不同。
杲曰∶味之薄者则通，酸、苦、咸、平是也。味之浓者则泄，咸、苦、酸、寒是也。
气之浓者发热，辛、甘、温、热是也。气之薄者渗泄，甘、淡、平、凉是也。渗谓小汗，
泄谓利小便也。
宗 曰∶天地既判，生万物者五气耳。五气定位，则五味生。故曰生物者，气也；成之
者，味也。以奇生则成而偶，以偶生则成而奇。寒气坚，故其味可用以软；热气软，故其味
可用以坚；风气散，故其味可用以收；燥气收，故其味可用以散。土者冲气之所生，冲气则
无所不和，故其味可用以缓。气坚则壮，故苦可以养气。脉软则和，故咸可以养脉。骨收则
强，故酸可以养骨。筋散则不挛，故辛可以养筋。肉缓则不壅，故甘可以养肉。坚之，而后
可以软；收之，而后可以散。欲缓则用甘，不欲则弗用，用之不可太过，太过亦病矣。古之
养生治疾者，必先通乎此，否则能以人之疾者，盖寡矣。
李杲曰∶夫药有温、凉、寒、热之气，辛、甘、淡、酸、苦、咸之味也。升、降、浮、
沉之相互，浓、薄、阴、阳之不同。一物之内，气味兼有；一药之中，理性具焉。
或气一而味殊，或味同而气异。气象天，温热者，天之阳；凉寒者，天之阴。天有阴、
阳，风、寒、暑、湿、燥、火，三阴、三阳，上奉之也。味象地，辛、甘、淡者，地之阳；
酸、苦、咸者，地之阴；地有阴、阳，金、木、水、火、土，生、长、化、收、藏，下应之
也。气味薄者，轻清成象，本乎天者亲上也。气味浓者，重浊成形，本乎地者亲下也。
好古曰∶本草之味有五，气有四。然一味之中有四气，如辛味则石膏寒、桂附热、半夏
温、薄荷凉之类是也。夫气者天也，温热天之阳，寒凉天之阴；阳则升，阴则降。味者地也
，辛、甘、淡，地之阳，酸、苦、咸，地之阴；阳则浮，阴则沉。有使气者，使味者，气味
俱使者，先使气而后使味者，先使味而后使气者。有一物一味者，一物三味者；一物一气者
，一物二气者。或生熟异气味，或根苗异气味。或温多而成热，或凉多而成寒，或寒热各半
而成温。或热者多，寒者少，寒不为之寒；或寒者多，热者少，热不为之热，不可一途而取
也。或寒热各半，昼服则从热之属而升，夜服则从寒之属而降；或晴则从热，阴则从寒，变
化不一如此。况四时六位不同，五运六气各异，可以轻用为哉。
《六节脏象论》云∶天食人以五气，地食人以五味。五气入鼻，藏于心肺，上使五色修
明，音声能彰。五味入口，藏于肠胃，味有所藏，以养五气，气和而生，津液相成，神乃自
生。又曰∶形不足者，温之以气；精不足者，补之以味。
王冰曰∶五气者，燥气凑肝，焦气凑心，香气凑脾，腥气凑肺，腐气凑肾也。心荣色，
肺主音，故气藏于心肺，而明色彰声也。气为水之母，故味藏于肠胃而养五气。孙思邈曰∶
精以食气，气养精以荣色；形以食味，味养形以生力。精顺五气以灵，形受五味以成。若
食气相反则伤精，食味不调则损形。是以圣人先用食禁以存生，后制药物以防命，气味温
补以存精形。
《阴阳应象论》说：阳气积聚形成天，阴气积聚形成地。阴气性质宁静，阳气性质躁动；阳气主生发，阴气主成长；阳气主肃杀，阴气主闭藏。
阳气化生为气，阴气凝聚成形。阳表现为气，阴表现为味。味滋养形体，形体依赖气，气转化为精，精通过气化作用生成；精消耗气，形体消耗味，气化作用产生精，气生成形体。味过度会损伤形体，气过度会损伤精，精可以转化为气，但气会被过度的味所伤害。阴味的物质从下窍排出，阳气的物质从上窍散发。清轻的阳气发散于腠理（皮肤肌肉的间隙），重浊的阴气流入五脏；清轻的阳气充实四肢，重浊的阴气归于六腑。味道浓厚的属于阴，味道淡薄的属于阴中之阳；气味浓厚的属于阳，气味淡薄的属于阳中之阴。味道浓厚具有泄下的作用，味道淡薄具有通利的作用；气味淡薄具有发散透表的作用，气味浓厚具有发热的效应。辛味和甘味具有发散作用，属于阳；酸味和苦味具有涌吐或泄下的作用，属于阴；咸味具有涌吐或泄下的作用，属于阴；淡味具有渗湿泄下的作用，属于阳。这六种性质有的收敛，有的发散，有的缓和，有的急迫，有的滋润，有的干燥，有的软化，有的坚硬，根据它们对人体的益处来运用，调和人体之气，使之恢复平衡。
张元素说：清中之清者，发散于腠理；清中之浊者，充实于四肢。浊中之浊者，归于六腑；浊中之清者，流入五脏。附子气味浓厚，属于阳中之阳；大黄味道浓厚，属于阴中之阴。茯苓气味淡薄，属于阳中之阴，所以能通利小便，归入手太阳经，不离阳的本体；麻黄味道淡薄，属于阴中之阳，所以能发汗解表，归入手太阴经，不离阴的本体。凡是气味相同的事物必然具备各种味道，味道相同的事物必然具备各种气味。气味各有浓薄之分，所以药性功效各不相同。
李杲说：味道淡薄的则能通利，如酸、苦、咸、平性是也。味道浓厚的则能泄下，如咸、苦、酸、寒性是也。气味浓厚的则能发热，如辛、甘、温、热性是也。气味淡薄的则能渗湿泄下，如甘、淡、平、凉性是也。所谓“渗”是指微微出汗，“泄”是指通利小便。
王好古说：天地分离之后，生成万物的只有五气罢了。五气位置确定，五味才随之产生。所以说，生成万物的是气；成就万物的是味。以奇数生成的，成就时为偶数；以偶数生成的，成就时为奇数。寒气性质坚实，所以其味可以用来软化；热气性质柔软，所以其味可以用来坚敛；风气性质发散，所以其味可以用来收敛；燥气性质收敛，所以其味可以用来发散。土是由冲和之气所生，冲和之气无所不和，所以其味可以用来缓和。气坚实则身体强壮，所以苦味可以养气。脉象柔软则气血调和，所以咸味可以养脉。骨骼收敛则坚固，所以酸味可以养骨。筋脉发散则不痉挛，所以辛味可以养筋。肌肉舒缓则不壅滞，所以甘味可以养肉。必须先坚敛，然后才能软化；先收敛，然后才能发散。想要缓和就用甘味，不想缓和就不用，使用不可太过，太过也会成为病态。古代养生治病的人，必须先通晓这个道理，否则能够治愈他人疾病的人，大概很少了。
李杲说：药物有温、凉、寒、热的气味，以及辛、甘、淡、酸、苦、咸的味道。还有升、降、浮、沉的相互作用，浓、薄、阴、阳的不同。在一味药之内，气味兼有；在一剂药之中，药理特性完备。
有的气相同而味道不同，有的味道相同而气不同。气象征天，温热是天之阳；凉寒是天之阴。天有阴阳，风、寒、暑、湿、燥、火，三阴、三阳，是上天所奉行的。味象征地，辛、甘、淡是地之阳；酸、苦、咸是地之阴；地有阴阳，金、木、水、火、土，生、长、化、收、藏，是大地所应合的。气味淡薄的，轻清而成象，本乎天的亲近上位；气味浓厚的，重浊而成形，本乎地的亲近下位。
寇宗奭说：本草中的味道有五种，气味有四种。然而一味药中可能有四种气，比如辛味的药，石膏性寒、桂枝附子性热、半夏性温、薄荷性凉等就是如此。气属于天，温热是天之阳，寒凉是天之阴；阳则上升，阴则下降。味属于地，辛、甘、淡是地之阳，酸、苦、咸是地之阴；阳则上浮，阴则下沉。有主要发挥气作用的，有主要发挥味作用的，有气味共同发挥作用的，有先发挥气后发挥味的，有先发挥味后发挥气的。有一味药的，有三种味的；有一种气的，有两种气的。或者生品与熟品气味不同，或者根与苗气味不同。或者温多而成热，或者凉多而成寒，或者寒热各半而成温。或者热者多，寒者少，寒性被抑制而不显寒；或者寒者多，热者少，热性被抑制而不显热，不能一概而论。或者寒热各半，白天服用则从热的一类而上升，夜晚服用则从寒的一类而下降；或者晴天服用从热，阴天服用从寒，变化不一如此。何况四季和六气方位不同，五运六气各异，怎么可以轻易用药呢？
《六节脏象论》说：天给人提供五气，地给人提供五味。五气通过鼻子吸入，储藏于心肺，向上使面色红润光泽，声音洪亮清晰。五味入口，储藏于肠胃，味道有所储藏，用来滋养五气，气和顺而生津液，津液相成，神气自然产生。又说：形体不足的，用气来温补；精气不足的，用味来滋补。
王冰说：五气中，燥气凑合于肝，焦气凑合于心，香气凑合于脾，腥气凑合于肺，腐气凑合于肾。心主管血色，肺主管声音，所以气储藏于心肺，而使面色明润、声音彰显。气是水之母，所以味储藏于肠胃而滋养五气。孙思邈说：精依靠气来滋养，气滋养精以荣润面色；形体依靠味来滋养，味滋养形体以产生力量。精顺应五气而灵动，形体接受五味而成就。如果食气相反则损伤精，食用味道不调则损害形体。因此圣人先用饮食禁忌来保全生命，后制定药物来防止死亡，利用气味的温补作用来保存精和形。
The *Yin Yang Ying Xiang Lun* (Treatise on Yin and Yang Corresponding to Images) states: The accumulation of Yang Qi (vital energy) forms Heaven, and the accumulation of Yin Qi forms Earth. Yin is quiet, while Yang is restless; Yang generates, Yin grows; Yang destroys, Yin stores.
Yang transforms into Qi, while Yin takes form. Yang manifests as Qi, and Yin manifests as Flavor. Flavor nourishes Form, Form relies on Qi, Qi transforms into Essence, and Essence is generated through transformation; Essence consumes Qi, and Form consumes Flavor, transformation generates Essence, and Qi generates Form. Excessive Flavor damages Form, excessive Qi damages Essence, Essence can transform into Qi, but Qi is damaged by excessive Flavor. Yin flavors exit through the lower orifices, while Yang Qi exits through the upper orifices. Clear Yang disperses into the Cou Li (interstitial spaces of skin and muscle), while Turbid Yin flows into the Zang organs (solid organs); Clear Yang fills the four limbs, while Turbid Yin returns to the Fu organs (hollow organs). Flavors that are strong belong to Yin, while those that are weak belong to Yang within Yin; Qi that is strong belongs to Yang, while that which is weak belongs to Yin within Yang. Strong flavors have a purgative effect, while weak flavors have a unblocking effect; weak Qi has a dispersing and releasing effect, while strong Qi has a heating effect. Pungent and Sweet flavors have a dispersing action and belong to Yang; Sour and Bitter flavors have an inducing-vomiting or purgative action and belong to Yin; Salty flavor has an inducing-vomiting or purgative action and belongs to Yin; Bland flavor has a leaching and draining action and belongs to Yang. These six properties either astringe or disperse, either relax or tense, either moisten or dry, either soften or harden. They are utilized according to their benefits to harmonize Qi and restore balance.
Zhang Yuansu stated: The clearest of the clear disperses into the Cou Li; the turbid part of the clear fills the four limbs. The most turbid of the turbid returns to the Fu organs; the clear part of the turbid flows into the Zang organs. Fuzi (Aconiti Lateralis Radix Preparata) has strong Qi and belongs to Yang within Yang; Dahuang (Rhei Radix et Rhizoma) has strong Flavor and belongs to Yin within Yin. Fuling (Poria) has weak Qi and belongs to Yin within Yang, thus it promotes urination and enters the Hand Taiyang channel, remaining close to the nature of Yang; Mahuang (Ephedrae Herba) has weak Flavor and belongs to Yang within Yin, thus it induces sweating and enters the Hand Taiyin channel, remaining close to the nature of Yin. All things with the same Qi must possess various flavors, and all things with the same flavor must possess various Qis. Because Qi and Flavor vary in strength, their therapeutic effects differ.
Li Gao stated: Weak flavors promote unblocking, such as Sour, Bitter, Salty, and Neutral natures. Strong flavors promote purging, such as Salty, Bitter, Sour, and Cold natures. Strong Qi causes heat, such as Pungent, Sweet, Warm, and Hot natures. Weak Qi promotes leaching and draining, such as Sweet, Bland, Neutral, and Cool natures. "Leaching" refers to slight perspiration, and "draining" refers to promoting urination.
Wang Haogu stated: After Heaven and Earth separated, only the Five Qi generated all things. Once the positions of the Five Qi were established, the Five Flavors arose. Thus, it is said that Qi generates living things, while Flavor completes them. What is born from odd numbers becomes even upon completion, and what is born from even numbers becomes odd upon completion. Cold Qi is firm, so its flavor can be used to soften; Heat Qi is soft, so its flavor can be used to harden; Wind Qi is dispersing, so its flavor can be used to astringe; Dryness Qi is collecting, so its flavor can be used to disperse. Earth is generated by the Harmonious Qi, which harmonizes everything, so its flavor can be used to relax. Firm Qi strengthens, so Bitter flavor can nourish Qi. Soft pulses indicate harmony, so Salty flavor can nourish vessels. Collecting bones indicate strength, so Sour flavor can nourish bones. Dispersing sinews prevent spasms, so Pungent flavor can nourish sinews. Relaxed muscles prevent stagnation, so Sweet flavor can nourish flesh. One must first harden before one can soften; one must first collect before one can disperse. To relax, use Sweet flavor; if relaxation is not desired, do not use it. Do not overuse it, for excess also causes disease. Ancient practitioners of health preservation and disease treatment must first understand this principle; otherwise, few could cure others' illnesses.
Li Gao stated: Medicines have Warm, Cool, Cold, and Hot Qis, and Pungent, Sweet, Bland, Sour, Bitter, and Salty flavors. There are interactions of Ascending, Descending, Floating, and Sinking, and differences in Strength, Weakness, Yin, and Yang. Within a single herb, both Qi and Flavor are present; within a single medicine, its therapeutic nature is complete.
Some have the same Qi but different flavors, some have the same flavor but different Qis. Qi resembles Heaven: Warm and Hot are Heaven's Yang; Cool and Cold are Heaven's Yin. Heaven has Yin and Yang, Wind, Cold, Summer-heat, Dampness, Dryness, and Fire, along with Three Yin and Three Yang, which are upheld by Heaven. Flavor resembles Earth: Pungent, Sweet, and Bland are Earth's Yang; Sour, Bitter, and Salty are Earth's Yin; Earth has Yin and Yang, Metal, Wood, Water, Fire, and Earth, corresponding to Generation, Growth, Transformation, Harvest, and Storage, which are responded to by Earth. Those with weak Qi and Flavor are light and clear, forming images, belonging to Heaven and亲近 the upper; those with strong Qi and Flavor are heavy and turbid, forming shapes, belonging to Earth and亲近 the lower.
Kou Zongshi stated: Materia Medica flavors are five, and Qi types are four. However, within one flavor, there may be four Qis; for example, among Pungent flavors, Shigao (Gypsum Fibrosum) is Cold, Guizhi (Cinnamomi Ramulus) and Fuzi are Hot, Banxia (Pinelliae Rhizoma) is Warm, and Bohe (Menthae Haplocalycis Herba) is Cool. Qi belongs to Heaven: Warm and Hot are Heaven's Yang, Cold and Cool are Heaven's Yin; Yang ascends, Yin descends. Flavor belongs to Earth: Pungent, Sweet, and Bland are Earth's Yang, Sour, Bitter, and Salty are Earth's Yin; Yang floats, Yin sinks. Some medicines primarily utilize Qi, some primarily utilize Flavor, some utilize both Qi and Flavor, some act via Qi first then Flavor, and some via Flavor first then Qi. There are herbs with one flavor, three flavors; with one Qi type, two Qi types. Raw and processed forms may have different Qi and Flavor; roots and shoots may have different Qi and Flavor. If Warm predominates, it becomes Hot; if Cool predominates, it becomes Cold; if Cold and Hot are equal, it becomes Warm. If Hot predominates and Cold is scarce, the Cold nature is suppressed and does not manifest as Cold; if Cold predominates and Hot is scarce, the Hot nature is suppressed and does not manifest as Hot. One cannot apply a uniform rule. If Cold and Hot are equal, taking it during the day follows the Hot category and ascends, while taking it at night follows the Cold category and descends; sunny days follow Heat, cloudy days follow Cold. Changes are diverse like this. Moreover, the Four Seasons and Six Positions differ, and the Five Movements and Six Qi vary. How can one prescribe lightly?
The *Liu Jie Zang Xiang Lun* (Treatise on the Six Nodes and Viscera Manifestations) says: Heaven feeds humans with Five Qi, and Earth feeds humans with Five Flavors. Five Qi enter through the nose and store in the Heart and Lung, causing the complexion to become bright and the voice to resonate clearly. Five Flavors enter the mouth and store in the intestines and stomach; the stored flavors nourish the Five Qi. When Qi is harmonious, life arises; when fluids and essence combine, Spirit naturally emerges. It also states: For deficiency of Form, warm it with Qi; for deficiency of Essence, tonify it with Flavor.
Wang Bing stated: Among the Five Qi, Dryness Qi approaches the Liver, Scorched Qi approaches the Heart, Fragrant Qi approaches the Spleen, Fishy Qi approaches the Lung, and Putrid Qi approaches the Kidney. The Heart governs blood color, and the Lung governs sound, so Qi stores in the Heart and Lung, making color bright and sound resonant. Qi is the mother of Water, so Flavor stores in the intestines and stomach to nourish the Five Qi. Sun Simiao stated: Essence is nourished by Qi, and Qi nourishes Essence to brighten the complexion; Form is nourished by Flavor, and Flavor nourishes Form to generate strength. Essence becomes spiritual by following the Five Qi, and Form is completed by receiving the Five Flavors. If the consumed Qi is contrary, it damages Essence; if the consumed Flavor is unbalanced, it harms Form. Therefore, sages first used dietary taboos to preserve life, and later formulated drugs to prevent death, using the warming and tonifying properties of Qi and Flavor to preserve Essence and Form.