凡治病服药，必知时禁、经禁、病禁、药禁。夫时禁者，必本四时升降之理，汗、下、吐、利之宜。大法春宜吐，
象万物之发生，耕
耨科斫，使阳气之郁者易达也。夏宜汗，象万物之浮而有余也。秋宜下，象万物之收成，推
陈致新，而使阳气易收也。冬周密，象万物之闭藏，使阳气不动也。经云∶夫四时阴阳者，
与万物浮沉于生长之门，逆其根，伐其本，坏其真矣。又云∶用温远温，用热远热，用凉远
凉，用寒远寒，无翼其胜也。故冬不用白虎，夏不用青龙，春夏不服桂枝，秋冬不服麻黄，
不失气宜。如春夏而下，秋冬而汗，是失天信，伐天和也。有病则从权，过则更之。
经禁者，足太阳膀胱经为诸阳之首，行于背，表之表，风寒所伤则宜汗，传入本则宜利
小便；若下之太早，必变证百出，此一禁也。足阳明胃经，行身之前，主腹满胀，大便难，
宜下之，盖阳明化燥火，津液不能停，禁发汗、利小便，为重损津液，此二禁也。足少阳胆
经，行身之侧，在太阳、阳明之间，病则往来寒热，口苦胸胁痛，只宜和解；且胆者、无
出无入，又主发生之气，下则犯太阳，汗则犯阳明，利小便则使生发之气反陷入阴中，此三
禁也。三阴非胃实不当下，为三阴无传，本须胃实得下也。分经用药，有所据焉。
病禁者，如阳气不足，阴气有余之病，则凡饮食及药，忌助阴泻阳。诸淡食及淡味之药
，泻升发以助收敛也；诸苦药皆沉，泻阳气之散浮；诸姜、附、官桂辛热之药，及湿面、酒
、大料物之类，助火而泻元气；生冷、硬物损阳气，皆所当禁也。如阴火欲衰而退，以三焦
元气未盛，必口淡淡，如咸物亦所当禁。
药禁者，如胃气不行，内亡津液而干涸，求汤饮以自救，非渴也，乃口干也，非温胜也
，乃血病也。当以辛酸益之，而淡渗五苓之类，则所当禁也。汗多禁利小便，小便多禁发汗
。咽痛禁发汗利小便，若大便快利，不得更利。大便秘涩，以当归、桃仁、麻子仁、郁李仁
、皂角仁，和血润肠，如燥药则所当禁者。吐多不得复吐；如吐而大便虚辄者，此土气壅滞
，以姜、橘之属宣之；吐而大便不通，则利大便，上药则所当禁也。诸病恶疮，及小儿 后
，大便实者，亦当下之，而姜、橘之类，则所当禁也。又如脉弦而服平胃散，脉缓而服黄
建中汤，乃实实虚虚，皆所当禁也。人禀天之湿化而生胃也，胃之与湿，其名虽二，其实一
也。湿能滋养于胃，胃湿有余，亦当泻湿之太过也。胃之不足，惟湿物能滋养。仲景云∶胃
胜思汤饼，而胃虚食汤饼者，往往增剧，湿能助火，火旺郁而不通主大热。初病火旺不可食
，以助火也。察其时，辨其经，审其病，而后用药，四者不失其宜，则善矣。
凡是治疗疾病和服用药物，必须了解时令禁忌、经络禁忌、病症禁忌和药物禁忌。所谓时令禁忌，必须以四季气机升降的规律为基础，明确发汗、攻下、催吐、利小便等治法的适宜时机。一般原则是：春季适宜用吐法，以象征万物的生发，如同耕种除草砍伐枝条，使郁滞的阳气容易通达；夏季适宜用汗法，以象征万物生长旺盛有余的状态；秋季适宜用下法，以象征万物的收成，推陈出新，使阳气容易收敛；冬季宜周密闭藏，以象征万物潜藏的状态，使阳气不妄动。《内经》说：四时阴阳的变化，与万物在生长化收藏的门径中沉浮相应，违背了这个根本，就是摧残生命的本源，败坏了真气。又说：使用温性药要避开温盛的时节，使用热性药要避开热盛的时节，使用凉性药要避开凉盛的时节，使用寒性药要避开寒盛的时节，不要助长当令之气的偏胜。所以冬天不用白虎汤（清热重剂），夏天不用青龙汤（发汗峻剂），春夏季节不服桂枝汤（辛温解表），秋冬季节不服麻黄汤（辛温发汗），这样才不违背气机时令的适宜。如果在春夏季节误用下法，在秋冬季节误用汗法，这就是违背了天时的信约，破坏了人体的天和之气。但如果已有疾病则需权变处理，病愈后应及时调整。
所谓经络禁忌，足太阳膀胱经是诸阳经之首，行于背部，属于表的表层，受风寒侵袭适宜用汗法，邪气传入本经则适宜利小便；如果过早使用下法，必然导致各种变证出现，这是第一条禁忌。足阳明胃经，行于身体前面，主治腹满胀、大便困难，适宜用下法，因为阳明经化燥火，津液不能停留，禁止发汗和利小便，以免再次损伤津液，这是第二条禁忌。足少阳胆经，行于身体侧面，位于太阳经和阳明经之间，患病则出现往来寒热、口苦、胸胁痛，只适宜用和解法；而且胆腑无出无入，又主司生发之气，如果用下法则侵犯太阳经，用汗法则侵犯阳明经，利小便则会使生发之气反而陷入阴分，这是第三条禁忌。三阴经如果不是胃家实证，就不应当用下法，因为三阴经没有传变，原本必须等到胃实才能用下法。分经用药，是有依据的。
所谓病症禁忌，如阳气不足、阴气有余的疾病，那么凡饮食及药物，都忌讳助长阴气而泻损阳气。各种淡味食物及淡味药物，会泻除升发之气而助长收敛之气；各种苦味药物性质皆沉降，会泻除阳气的散浮；各种生姜、附子、官桂等辛热药物，以及湿面、酒、大料物之类，会助长火势而泻损元气；生冷、坚硬食物损伤阳气，都在禁忌之列。如果阴火欲衰退但三焦元气尚未强盛，必然感到口中淡淡无味，像咸味食物也应当禁忌。
所谓药物禁忌，如胃气不行，体内津液亡失而干涸，寻求汤饮来自救，这不是口渴，而是口干；不是温热胜邪，而是血分有病。应当用辛味和酸味药物来补益，而淡渗利湿的五苓散之类，则是应当禁忌的。出汗多者禁止利小便，小便多者禁止发汗。咽痛者禁止发汗和利小便，如果大便通畅快利，不得再用通利大便的方法。大便秘结涩滞，应用当归、桃仁、柏子仁、郁李仁、皂角仁等和血润肠的药物，如果再用燥烈药物则是应当禁忌的。呕吐多者不得再次催吐；如果呕吐且大便稀溏，这是土气壅滞，应用生姜、橘皮之类宣散；如果呕吐且大便不通，则应通利大便，此时上方（指姜橘宣散或催吐）则是应当禁忌的。各种疾病引起的恶疮，以及小儿痘疹之后，大便结实者，也应当用下法，而生姜、橘皮之类，则是应当禁忌的。又如脉弦却服用平胃散，脉缓却服用黄芪建中汤，这是实其实、虚其虚，都是应当禁忌的。人禀受天的湿气而生胃，胃与湿，名称虽然不同，实质是一致的。湿气能滋养胃，如果胃中湿气有余，也应当泻除湿气的太过部分。胃气不足，只有湿性食物才能滋养。张仲景说：胃气胜则想吃汤饼，而胃虚的人吃汤饼，往往会加重病情，因为湿气能助长火气，火旺郁结不通会导致大热。初病火旺时不可食用，以免助火。观察时令，辨别经络，审察病症，然后用药，这四者都不失其适宜，那就好了。
In treating diseases and administering medicines, one must understand the contraindications of seasons (Shi Jin), meridians (Jing Jin), conditions (Bing Jin), and drugs (Yao Jin). The contraindication of seasons must be based on the principles of the ascending and descending of Qi in the four seasons, and the appropriateness of sweating (Han), purging (Xia), vomiting (Tu), and promoting urination (Li). The general rule is: In spring, vomiting is appropriate, symbolizing the generation of all things, like plowing, weeding, and pruning, to allow stagnant Yang Qi to easily reach the surface. In summer, sweating is appropriate, symbolizing the floating and surplus state of all things. In autumn, purging is appropriate, symbolizing the harvest of all things, pushing out the old and bringing in the new, so that Yang Qi can easily converge. In winter, one should be meticulous and hidden, symbolizing the closure and storage of all things, keeping Yang Qi from moving recklessly. The Classic says: The Yin and Yang of the four seasons float and sink with all things in the gate of growth; violating this root destroys the foundation and ruins the true Qi. It also says: When using warm remedies, stay away from warm seasons; when using hot remedies, stay away from hot seasons; when using cool remedies, stay away from cool seasons; when using cold remedies, stay away from cold seasons. Do not assist the prevailing excess. Therefore, do not use Baihu Tang (White Tiger Decoction) in winter, Qinglong Tang (Azure Dragon Decoction) in summer, Guizhi Tang (Cinnamon Twig Decoction) in spring and summer, and Mahuang Tang (Ephedra Decoction) in autumn and winter. This does not violate the appropriateness of Qi seasons. If one uses purging in spring and summer, or sweating in autumn and winter, it is losing the trust of Heaven and destroying the Harmony of Heaven. However, if there is an existing disease, one may act according to circumstances (Quan); once resolved, adjustments must be made.
The contraindication of meridians: The Foot-Taiyang Bladder Meridian is the head of all Yang meridians, running along the back, the exterior of the exterior. When injured by Wind-Cold, sweating is appropriate; if the pathogen transmits into the interior of this meridian, promoting urination is appropriate. If purging is used too early, hundreds of transformed syndromes will emerge; this is the first contraindication. The Foot-Yangming Stomach Meridian runs along the front of the body, governing abdominal fullness and distension, and difficult defecation, for which purging is appropriate. Since Yangming transforms into Dryness-Fire, and Body Fluids cannot remain, sweating and promoting urination are prohibited to avoid further damaging Body Fluids; this is the second contraindication. The Foot-Shaoyang Gallbladder Meridian runs along the side of the body, between Taiyang and Yangming. Disease presents as alternating chills and fever, bitter taste in the mouth, and chest/hypochondriac pain, requiring only Harmonization (He Jie). Moreover, the Gallbladder has no exit or entry, and governs the generating Qi. Purging violates Taiyang, sweating violates Yangming, and promoting urination causes the generating Qi to sink into the Yin; this is the third contraindication. The Three Yin meridians should not be purged unless there is a Full condition of the Stomach, because the Three Yin have no transmission, and originally purging is only indicated when the Stomach is Full. Prescribing according to meridians has its basis.
The contraindication of conditions: For diseases where Yang Qi is insufficient and Yin Qi is excessive, all diet and medicine should avoid assisting Yin and draining Yang. All bland foods and bland-flavored drugs drain the ascending/generating Qi and assist convergence. All bitter drugs are sinking and drain the scattering/floating Yang Qi. All pungent-hot drugs like Sheng Jiang (Zingiberis Rhizoma Freshum), Fu Zi (Aconiti Lateralis Radix Praeparata), and Guan Gui (Cinnamomi Cortex), as well as damp noodles, wine, and strong spices, assist Fire and drain Yuan Qi. Cold/raw and hard foods damage Yang Qi and are all prohibited. If Yin-Fire desires to decline but Sanjiao Yuan Qi is not yet vigorous, leading to a bland taste in the mouth, even salty foods should be prohibited.
The contraindication of drugs: If Stomach Qi does not move, internal Body Fluids are lost and dried up, seeking soup/drink to save oneself is not thirst, but dry mouth; it is not Warmth overcoming Cold, but a Blood disorder. One should benefit with Pungent and Sour substances, while bland-draining formulas like Wuling San (Five-Ingredient Powder with Poria) are prohibited. Excessive sweating prohibits promoting urination; excessive urination prohibits sweating. Sore throat prohibits sweating and promoting urination. If defecation is rapid and free, do not use laxatives again. For constipation and涩 (obstruction), use Dang Gui (Angelicae Sinensis Radix), Tao Ren (Persicae Semen), Maziren (Bambusae Semen), Yuliren (Pruni Semen), and Zaojiaoren (Gleditsiae Fructus Spina) to harmonize Blood and moisten Intestines; drying drugs are prohibited. Excessive vomiting prohibits re-vomiting. If vomiting occurs with loose stools, this is Earth Qi stagnation, treated with Sheng Jiang (Zingiberis Rhizoma Freshum) and Ju Pi (Citri Reticulatae Pericarpium) to disperse; if vomiting occurs with constipation, promote defecation, while the aforementioned dispersing/vomiting methods are prohibited. For various diseases with malignant sores, and after pediatric exanthems, if stools are solid, purging is appropriate, while Sheng Jiang and Ju Pi are prohibited. Furthermore, taking Pingwei San (Peaceful Stomach Powder) for a Xian (Wiry) pulse, or Huangqi Jianzhong Tang (Astragalus Decoction to Establish the Middle) for a Huan (Slow/Relaxed) pulse, constitutes "reinforcing the Excess and depleting the Deficiency," which is prohibited. Humans are born from Heaven's Dampness transforming into the Stomach. Stomach and Dampness, though named differently, are essentially one. Dampness nourishes the Stomach; if Stomach-Dampness is excessive, one must purge the excess Dampness. If Stomach Qi is deficient, only damp-nourishing foods can sustain it. Zhang Zhongjing said: When Stomach Qi is excessive, one craves Tangbing (soup cakes); those with Stomach deficiency eating Tangbing often worsen their condition, because Dampness assists Fire, and Fire flourishing with stagnation leads to Great Heat. In initial Fire flourishing, one should not eat such foods to avoid assisting Fire. Observe the season, differentiate the meridian, examine the condition, then prescribe medication. If these four aspects do not miss their appropriateness, then it is excellent.