里证宜下不大便，恶热潮热汗蒸蒸，燥干谵语满硬痛，便溏为虚不可攻。
【注】里证，谓热邪内结，不大便，恶热潮热，自汗蒸蒸，口燥舌干谵语，腹满硬痛
也。阳明腑主里，故曰里证。里实者，有脾约，有胃实，有大便难，三者均为可下之证，
然不无轻重之别。三承气汤、脾约丸，量其可者而与之，庶乎无过也。若便溏为里虚，即
有是证不可攻也。论中有急下数证，不待便实而下之者，是下其热也，非下其结也。义
详阳明、少阴篇。
阳证身轻气高热，目睛了了面唇红，热烦口燥舌干渴，指甲红兮小便同。
【注】阳证，谓阳热之证也。不论三阴、三阳，凡见是证者，均为阳热有余也，阳主
动，故身轻也。阳气盛，故气高而喘也。阳主热，故口鼻气热也，阳主寤，故目睛了了
而不眠也。目睛不了了，亦有热极朦陇似不了了，然必目赤多眵，非若阴证之不了了而
神短无光也。阳气热，故身热，面唇红，指甲红也。阳热入里，故心烦，口燥，舌干而
渴，小便红也。表实者，三黄石膏汤发之。里实者，三承气汤下之，表里不实而热盛者，白
虎解毒等汤清之可也，详三阳篇。
阴证身重息短冷，目不了了色不红，无热欲卧厥吐利，小便白兮爪甲青。
【注】阴证，谓阴寒之证也。不论三阴、三阳，凡见是证者，均为阴寒不足也。阴主
静，故身重也。阴主寐，故目不了了但欲卧也。阳气虚寒，故息短口鼻气冷也，阴淫于
外，故面无红色，四肢厥冷爪甲青也。阴邪入内，故呕吐，下利清谷，小便清白也。以
上皆三阴寒证，临证者以附子、四逆、理中、吴茱萸等汤，择其宜而与之可也。详三阴篇。
里证适宜用攻下法的情况是大便不通，伴有怕冷、潮热或持续高热、大汗淋漓，以及大便干燥、胡言乱语、腹部胀满坚硬疼痛；若大便稀溏则属于虚证，不可使用攻下法。
【注】里证，是指热邪在体内结聚，表现为大便不通，怕冷、潮热，自汗出且汗出如蒸，口燥舌干、胡言乱语，腹部胀满坚硬疼痛。阳明腑（指大肠等消化器官的功能系统）主司里证，所以称为里证。里实证中，有脾约（脾阴不足导致肠道失润而便秘）、胃实（胃中燥热积滞）、大便难三种情况，这三者都属于可以使用攻下法的证候，但病情轻重有所不同。三承气汤（调胃承气汤、小承气汤、大承气汤的统称）、脾约丸，应根据病情的具体情况选择适用的方剂给予治疗，这样才不至于用药过度。如果大便稀溏属于里虚证，即使出现上述症状也不可攻下。医论中有几种急下证，不需要等到大便完全结实就进行攻下，这是为了泻除体内的热邪，而不是为了攻下燥结。具体义理详见《伤寒论》的阳明篇和少阴篇。
阳证表现为身体轻健、气息粗重、发热，眼睛明亮有神、面色和嘴唇红润，心中烦热、口燥、舌干且口渴，指甲发红、小便颜色深红。
【注】阳证，是指阳热性质的证候。不论涉及三阴经还是三阳经，凡是见到这些症状的，都属于阳热有余。阳主动，所以身体轻健。阳气旺盛，所以呼吸急促甚至喘息。阳主热，所以口鼻呼出的气体发热；阳主清醒（寤），所以眼睛明亮有神且难以入睡。眼睛昏暗不明，也有可能是热极导致视线模糊似昏蒙，但必然伴有眼睛发红、眼屎多，不像阴证的昏蒙那样精神萎靡、目光无神。阳气热盛，所以身体发热，面色和嘴唇发红，指甲发红。阳热之邪入里，所以心烦，口燥，舌干而渴，小便发红。表实证的，用三黄石膏汤发汗解表；里实证的，用三承气汤攻下泄热；表里均不实而热势亢盛的，用白虎汤、解毒汤等清热即可，详细内容见三阳篇。
阴证表现为身体沉重、呼吸短促、畏寒肢冷，眼睛昏暗不明、面色不红，没有发热想躺卧、四肢厥冷、呕吐腹泻，小便清长、指甲发青。
【注】阴证，是指阴寒性质的证候。不论涉及三阴经还是三阳经，凡是见到这些症状的，都属于阴寒不足。阴主静，所以身体沉重。阴主睡眠，所以眼睛昏暗不明只想躺卧。阳气虚弱寒冷，所以呼吸短促、口鼻呼出的气体寒冷；阴寒之邪浸淫于体表，所以面色没有红色，四肢厥冷、指甲发青。阴邪侵入体内，所以呕吐，下利排出未消化的食物残渣，小便清亮白色。以上都是三阴经的寒证，临床医生应根据具体情况选择附子汤、四逆汤、理中汤、吴茱萸汤等适宜方剂给予治疗即可。详细内容见三阴篇。
The interior syndrome (Interior Syndrome) is suitable for purgation when there is constipation, aversion to cold, tidal fever or continuous high fever, profuse sweating, dry stool, delirium, abdominal fullness, hardness, and pain. If the stool is loose, it indicates a deficiency syndrome, and purgation should not be used.
[Note] Interior syndrome refers to the accumulation of pathogenic heat inside the body, manifesting as constipation, aversion to cold, tidal fever, spontaneous sweating that feels like steaming, dry mouth and tongue, delirium, and abdominal fullness, hardness, and pain. The Yangming Fu-organs (Yangming Bowel System) govern the interior, hence it is called interior syndrome. In interior excess syndromes, there are three types: Pi Yue (Splee Confinement, constipation due to insufficient spleen yin causing intestinal dryness), Wei Shi (Stomach Excess, dry-heat accumulation in the stomach), and difficult defecation. All three are indications for purgation, but they differ in severity. San Chengqi Tang (Three Decoctions of Inheriting Qi: Tiaowei Chengqi Tang, Xiao Chengqi Tang, Da Chengqi Tang) and Pi Yue Wan should be selected according to the specific condition to avoid excessive treatment. If the stool is loose, it indicates an interior deficiency; even if other symptoms appear, purgation is contraindicated. There are several urgent purgation indications in the treatises where purgation is used before the stool becomes fully solid; this is to purge heat, not to remove dryness. The detailed principles are found in the Yangming and Shaoyin chapters.
Yang syndrome manifests as lightness of the body, rapid breathing, fever, clear eyes with spirit, red face and lips, mental restlessness, dry mouth, dry tongue, thirst, red fingernails, and dark red urine.
[Note] Yang syndrome refers to a heat-excess pattern. Regardless of whether it involves the Three Yin or Three Yang meridians, these symptoms indicate an excess of Yang-heat. Yang governs movement, hence the body feels light. Abundant Yang qi leads to rapid breathing and panting. Yang governs heat, hence the breath from the mouth and nose is hot; Yang governs wakefulness, hence the eyes are clear and alert with insomnia. Although extreme heat can cause blurred vision resembling dullness, it is accompanied by red eyes and excessive discharge, unlike the dullness of Yin syndrome which features listlessness and lack of luster in the eyes. Yang-heat causes fever, red face and lips, and red nails. When Yang-heat enters the interior, it causes mental restlessness, dry mouth, dry tongue, thirst, and red urine. For exterior excess, use Sanhuang Shigao Tang (Three-Yellow Gypsum Decoction) to induce sweating; for interior excess, use San Chengqi Tang to purge heat; for heat excess without exterior or interior excess, use Baihu Tang (White Tiger Decoction) or Jiedu Tang (Detoxification Decoction) to clear heat. Details are in the Three Yang chapters.
Yin syndrome manifests as heaviness of the body, shortness of breath, coldness, dull eyes, pale complexion, absence of fever with a desire to lie down, cold limbs, vomiting, diarrhea, clear and long urination, and bluish-green fingernails.
[Note] Yin syndrome refers to a cold-deficiency pattern. Regardless of whether it involves the Three Yin or Three Yang meridians, these symptoms indicate insufficiency of Yin-cold. Yin governs stillness, hence the body feels heavy. Yin governs sleep, hence the eyes are dull and there is a desire to lie down. Deficient and cold Yang qi leads to shortness of breath and cold breath from the mouth and nose; Yin-cold invading the exterior leads to a lack of redness in the face and cold limbs with bluish nails. Yin-pathogen entering the interior causes vomiting and diarrhea with undigested food, and clear white urine. These are all Cold syndromes of the Three Yin meridians. Clinicians should select appropriate formulas such as Fuzi Tang (Aconite Decoction), Sini Tang (Reverse-Recovery Decoction), Lizhong Tang (Regulate the Middle Decoction), or Wuzhuyu Tang (Evodia Decoction) based on the specific condition. Details are in the Three Yin chapters.