凡发热恶寒其脉浮者，伤于阳也。若下太早，则邪尽入于里，而为结胸。如不发热
而恶寒，其脉沉紧者，伤于阴也。若早下之，则邪聚结于心下而为痞。《经》曰∶浊
气在上，则生 胀。又曰∶病发于阴，而反下之，因作痞是也。然必结心下者，以阴
受气之处也，结胸则满而痛为实，痞则满而不痛为虚，痞满下利者为虚，便闭者为实。
若小便不利，其状如痞，攻而不散者，是水饮内蓄，以致津液不行，治宜散水则愈。若
心下痞而恶寒者，是表里症俱未解，当先解表，后与攻痞可也。大抵诸痞皆热，故攻之
多寒剂，所以诸泻心汤，皆治伤寒痞满，盖满在心胸，不在胃也。或杂病痞满，有寒热
虚实之不同，《保命集》云∶脾不能行气于四脏，结而不散，则为痞。凡伤寒之痞，从
外之内，故宜苦泻。杂病之痞，从内之外，故宜辛散。更有素因有积，又遇伤寒，寒气
入里，与积相合而为痞，乃使脏气结而不通，此亦为脏结，必痛引少腹，入阴筋而死。
温热之病，因外感内伤，触动郁火自内而发之于外，初则表里俱热，宜用辛凉之
剂，两除表里之热。久则表热微而里热甚，又宜如承气汤。苦寒之剂以泻之，则热退身
凉，而病自己也。倘不谙伏气温热之症，表里俱热者，而认作即病伤寒之症，用麻黄汤
辛温之剂以发表，则内热愈甚，而斑黄狂乱之症起矣。或未用辛凉之剂以解表，便用承
气汤苦寒之剂以攻里，则表热未去，而结胸虚痞之症见矣。
凡是出现发热、恶寒，且脉象浮的，是感受了阳邪。如果过早使用泻下法，邪气就会全部陷入体内，形成结胸证。如果不发热而只恶寒，脉象沉紧的，是感受了阴邪。如果过早使用泻下法，邪气就会聚集在心下部而形成痞证。《黄帝内经》说：“浊气停留在上部，就会产生胀满。”又说：“病发于阴经，却反而使用泻下法，因此导致痞证。”这说的就是这种情况。但是痞证必定结聚在心下部，因为这里是阴经受气的地方。结胸证表现为心下满而且疼痛，属于实证；痞证表现为心下满但不疼痛，属于虚证。痞证伴有腹泻的属于虚证，大便闭结的属于实证。如果小便不通利，症状看起来像痞证，但攻下后痞满不消散的，这是水饮内停蓄积，导致津液运行不畅，治疗应当发散水饮才能痊愈。如果心下痞满并且恶寒，说明表证和里证都还没有解除，应当先解表，然后再用攻痞的方法治疗。大抵各种痞证多属热证，所以治疗多用寒凉药物，因此各种泻心汤，都是用来治疗伤寒引起的痞满，这是因为痞满的部位在心胸，不在胃中。或者是杂病引起的痞满，有寒、热、虚、实的不同，《保命集》说：“脾不能将气输送到四肢脏腑，气机郁结不散，就形成痞证。”凡是伤寒引起的痞证，是从外部传入内部，所以适宜用苦味药泻下。杂病引起的痞证，是从内部反映到外部，所以适宜用辛味药发散。更有原本体内就有积滞，又遭遇伤寒，寒气进入体内，与积滞相结合而形成痞证，这使得脏气郁结不通，这也称为脏结，必定疼痛牵引少腹，甚至痛入阴筋，会导致死亡。
温热病，是因为外感或内伤，触动体内郁积的火邪，从内部发作并表现于外部，初期则表里都发热，适宜使用辛凉的药物，同时清除表里之热。时间久了，则表热轻微而里热严重，又适宜使用承气汤等苦寒药物来泻下，这样热退身凉，病就好了。倘若不熟悉伏气温热这种病症，对于表里俱热的情况，误认为是即病伤寒（感受风寒立即发病）的症状，使用麻黄汤这类辛温药物来发汗解表，那么体内的热邪会更加严重，从而引发发斑、发黄、狂乱等症状。或者没有先用辛凉药物解表，就直接使用承气汤这类苦寒药物攻下里实，那么表热尚未去除，就会出现结胸或虚痞的症状。
Whenever there is fever and aversion to cold with a floating pulse, it indicates an injury by Yang pathogenic factors. If purgation is employed too early, the pathogenic factors will fully enter the interior, resulting in Jie Xiong (Chest Binding). If there is no fever but only aversion to cold, with a deep and tight pulse, it indicates an injury by Yin pathogenic factors. If purgation is employed too early, the pathogenic factors will gather and knot at the epigastrium, forming Pi Syndrome (Epigastric Fullness and Obstruction). The *Classic* states: "When turbid Qi remains in the upper part, distension occurs." It also states: "When a disease originates from the Yin level, and purgation is wrongly applied, Pi Syndrome results." This refers to the aforementioned situation. However, Pi Syndrome must knot at the epigastrium, as this is where the Yin levels receive Qi. Jie Xiong presents with fullness and pain, indicating an Excess condition; Pi Syndrome presents with fullness without pain, indicating a Deficiency condition. Pi Syndrome accompanied by diarrhea indicates Deficiency, while constipation indicates Excess. If urination is difficult, and the presentation resembles Pi Syndrome but does not resolve with attacking methods, this is due to internal accumulation of Water-Fluids, leading to impaired fluid metabolism; treatment should focus on dispersing Water-Fluids for recovery. If there is epigastric fullness accompanied by aversion to cold, it indicates that both exterior and interior syndromes remain unresolved. One should first release the exterior, and subsequently treat the Pi Syndrome. Generally, various Pi Syndromes are heat-related, so treatment often employs cold-natured agents. Therefore, various Xi Xin Tang (Drain the Epigastrium Decoctions) are used to treat Pi and fullness caused by Shang Han (Cold Damage), because the fullness is located in the chest and heart region, not in the Stomach. Alternatively, Pi and fullness arising from miscellaneous diseases may differ in Cold, Heat, Deficiency, and Excess. *Bao Ming Ji* (Collection for Preserving Life) states: "If the Spleen cannot transport Qi to the four Zang organs, and Qi knots without dispersing, Pi Syndrome forms." For Pi Syndrome caused by Shang Han, which proceeds from the exterior to the interior, bitter-draining methods are appropriate. For Pi Syndrome caused by miscellaneous diseases, which proceeds from the interior to the exterior, acrid-dispersing methods are appropriate. Furthermore, if a patient has pre-existing accumulations and then contracts Shang Han, cold pathogenic factors entering the interior combine with these accumulations to form Pi Syndrome. This causes Zang Qi to knot and become obstructed, also known as Zang Jie (Zang Knotting). It necessarily involves pain radiating to the lower abdomen and penetrating into the genitalia, leading to death.
Wen Re Bing (Warm-Heat Diseases) arise from external contraction or internal injury, which stirs up latent Fire accumulating within, causing it to erupt from the interior to the exterior. In the initial stage, both the exterior and interior present with heat, so acrid-cool agents should be used to clear heat from both levels. After a prolonged period, exterior heat becomes mild while interior heat becomes severe; at this point, Cheng Qi Tang (Order the Qi Decoction) and other bitter-cold agents should be used to purge the interior. Once the heat recedes and the body cools, the disease resolves. If one is unfamiliar with Fu Wen Re (Latent Warm-Heat) syndromes, and mistakes the simultaneous exterior and interior heat for Ji Bing Shang Han (Immediate Cold Damage upon contraction), using Ma Huang Tang (Ephedra Decoction), an acrid-warm agent for releasing the exterior, will cause internal heat to intensify, leading to symptoms such as macules, jaundice, mania, and confusion. Or, if one fails to use acrid-cool agents to release the exterior and instead immediately uses Cheng Qi Tang, a bitter-cold agent to attack the interior, the exterior heat will not have dissipated, yet symptoms of Jie Xiong or Xu Pi (Deficient Epigastric Fullness) will appear.