治阳明腑病，潮热、谵语、便闭、绕脐硬痛，为有燥屎，此结聚之热，邪
大黄（三钱） 芒硝（二钱） 甘草（五分
水煎服。
本方去甘草，加枳实、浓朴，名大承气汤。
窃按∶枳实消痞，浓朴去满，芒硝润燥，大黄泻实，必痞、满、燥、实四症兼全者，方
可用也。若痞满而未燥实者，宜用小承气汤，不用芒硝，恐伤下焦阴血也。燥实而未痞满者
即用本方，不用枳、朴，恐伤上焦阳气也。
论承气汤有八禁
一者，表不解恶寒未除，小便清长，知不在里仍在表也，法当汗解。二者，心下硬满
心下满，则邪气尚浅，若误攻之，利遂不止。恐正气下脱也三者，合面赤色面赤色，为邪在表，浮火
聚于上，而未结于下，故未可攻也。又面赤为戴阳，尤宜细辨。四者，平素食少，或病中
反能食平素食少，则胃气虚，故不可攻。然病中有燥屎，即不能食，若反能食，则无燥屎
不过便硬耳，亦未可攻也。五者，呕多呕吐属少阳，邪在上焦，故未可攻也。六者，
脉迟迟为寒，攻之则呃。七者，津液内竭病患自汗出，小便自利，此为津液内竭，不可
攻之，宜蜜煎导而通之。八者，小便少病患平日，小便日三四行，今日再行，知其不久即
入大肠，宜姑待之，不可妄攻也。
问曰∶潮热何以属阳明腑证？答曰∶潮热者，如潮之汛，不失其时，今日午后发热，明
日亦午后发热，故名潮热。若一日发至晚者，便是发热，而非潮热矣。若寒热相间，便是往
来寒热矣。仲景云∶其热不潮，不可与承气汤。可见潮热合用承气汤也。又问曰∶潮热固当
下，设有表证，何以治之？答曰∶潮热兼表，必先解表，然后攻里，若里证甚急，则用大柴
胡法，表里并治可也。
治疗阳明腑病，出现潮热、说胡话（谵语）、大便闭塞、肚脐周围硬痛，这是体内有燥屎的表现。这种热邪是结聚而成的，用大黄（三钱）芒硝（二钱）甘草（五分），用水煎服。
我按语道：枳实消除痞满，厚朴去除胀满，芒硝润燥，大黄泻下实热，必须痞、满、燥、实四种症状同时具备，才可以使用此方。如果只有痞满而没有燥实，应该用小承气汤，不用芒硝，因为恐怕会损伤下焦的阴血。如果只有燥实而没有痞满，就使用本方（调胃承气汤），不用枳实和厚朴，因为恐怕会损伤上焦的阳气。
论述承气汤使用的八种禁忌：
第一，表证未解，恶寒症状没有消除，小便清长，知道病邪不在里而在表，治疗方法应当发汗解表。
第二，心下部硬满。心下部满，说明邪气尚浅，如果误用攻下法，会导致腹泻不止，恐怕正气下脱。
第三，满面通红。满面通红，是因为邪气在表，浮火聚集在上部，而未结聚在下部，所以不可攻下。另外，满面通红也可能是戴阳证，尤其需要仔细辨别。
第四，平时饮食量少，或者生病期间反而能进食。平时饮食少，说明胃气虚弱，所以不可攻下。然而，如果病中有燥屎，通常是不能进食的；如果反而能进食，说明没有燥屎，只是大便干硬罢了，也不可攻下。
第五，呕吐多。呕吐属于少阳病，邪气在上焦，所以不可攻下。
第六，脉迟。脉迟主寒，如果攻下，会导致呃逆。
第七，津液内竭。病人自汗出，小便通畅自如，这是因为津液在内枯竭，不可攻下，适宜用蜜煎导法来通便。
第八，小便少。病人平日每天小便三四次，今天只排了两次，知道不久大便就会进入大肠，宜暂时等待，不可妄加攻下。
问：为什么潮热属于阳明腑证？答：潮热，像潮水涨落一样，按时发作。今天午后发热，明天也是午后发热，所以叫潮热。如果一天到晚都发热直到晚上，那就是发热，而不是潮热了。如果寒热交替出现，那就是往来寒热。张仲景说：如果热势不呈潮热状，不可给予承气汤。由此可见，潮热适合使用承气汤。又问：潮热固然应当攻下，如果兼有表证，该怎么治疗？答：潮热兼有表证，必须先解表，然后攻里；如果里证非常紧急，则可以用大柴胡汤的方法，表里同治。
Treating Yangming Fu-organ disease, presenting with tidal fever (Tidal Fever), delirium (Delirium), constipation (Constipation), and hard pain around the navel (Hard pain around the navel), indicates the presence of dry feces (Dry feces). This heat is accumulated and condensed. Use Da Huang (Rhei Radix et Rhizoma, 3 qian), Mang Xiao (Natrii Sulfas, 2 qian), Gan Cao (Glycyrrhizae Radix et Rhizoma, 5 fen), decocted in water and taken orally.
Removing Gan Cao from this formula and adding Zhi Shi (Aurantii Fructus Immaturus) and Hou Po (Magnoliae Officinalis Cortex), it is named Da Cheng Qi Tang (Major Order the Qi Decoction).
My commentary: Zhi Shi eliminates epigastric fullness and stuffiness (Pi), Hou Po removes abdominal distension (Man), Mang Xiao moistens dryness (Zao), and Da Huang purges excess (Shi). It can only be used when all four symptoms—epigaastrium stuffiness (Epigastric stuffiness), abdominal distension (Abdominal distension), dryness (Dryness), and excess (Excess)—are present simultaneously. If there is epigastric stuffiness and abdominal distension but no dryness or excess, Xiao Cheng Qi Tang (Minor Order the Qi Decoction) should be used without Mang Xiao, to avoid damaging the Yin blood of the Lower Jiao (Lower Jiao). If there is dryness and excess but no epigastric stuffiness or abdominal distension, use this formula (Tiao Wei Cheng Qi Tang - Regulate the Stomach Order the Qi Decoction) without Zhi Shi and Hou Po, to avoid damaging the Yang Qi of the Upper Jiao (Upper Jiao).
Eight contraindications for using Cheng Qi Tang are discussed:
1. If the exterior syndrome is not resolved and aversion to cold (Aversion to cold) persists, and urination is clear and profuse, it is known that the pathogen is still at the exterior level, not the interior. The treatment method should be diaphoresis (Diaphoresis) to resolve the exterior.
2. Hardness and fullness in the epigastrium (Epigastric hardness and fullness). Fullness in the epigastrium indicates the pathogen is still shallow; if mistakenly treated with purgation, diarrhea will persist incessantly, potentially leading to the collapse of healthy Qi downward.
3. Flushed face (Flushed face). A flushed face indicates the pathogen is at the exterior, with floating fire gathering above but not condensing below, so purgation is not yet appropriate. Furthermore, a flushed face may indicate Dai Yang syndrome (Floating Yang syndrome), which requires careful differentiation.
4. Small food intake normally, or ability to eat during illness. Small food intake normally indicates deficiency of Stomach Qi (Stomach Qi), so purgation is inappropriate. However, if dry feces are present, one usually cannot eat; if one can eat despite illness, it means there are no dry feces, only hard stool, so purgation is also inappropriate.
5. Frequent vomiting (Frequent vomiting). Vomiting belongs to Shaoyang syndrome (Shaoyang syndrome); the pathogen is in the Upper Jiao, so purgation is inappropriate.
6. Slow pulse (Slow pulse). A slow pulse indicates Cold (Cold); purgation will lead to hiccups (Hiccups).
7. Exhaustion of body fluids internally. The patient sweats spontaneously, and urination is normal/profuse. This indicates exhaustion of body fluids internally (Exhaustion of body fluids internally); purgation is inappropriate. Instead, honey suppositories (Honey suppository) should be used to promote bowel movement.
8. Scanty urination. Normally, the patient urinates three or four times a day; today only twice. This indicates that stool will soon enter the Large Intestine (Large Intestine); it is advisable to wait temporarily and not to blindly purge.
Question: Why does tidal fever belong to Yangming Fu-organ syndrome? Answer: Tidal fever occurs like the tide, on time. Today fever occurs in the afternoon, and tomorrow fever also occurs in the afternoon, hence the name tidal fever. If fever lasts all day until evening, it is simply fever, not tidal fever. If alternating chills and fever occur, it is alternating chills and fever (Alternating chills and fever). Zhang Zhongjing said: "If the heat is not tidal, do not administer Cheng Qi Tang." This shows that tidal fever is suitable for Cheng Qi Tang. Another question: Tidal fever certainly warrants purgation; what if there are concurrent exterior symptoms? Answer: If tidal fever is accompanied by an exterior syndrome, the exterior must first be resolved, then the interior attacked. If the interior condition is very urgent, the method of Da Chai Hu Tang (Major Bupleurum Decoction) can be used to treat both the exterior and interior simultaneously.