一曰痰症。停痰留饮。自汗胸满。发寒热。但头不痛。项不强。与伤寒异。二曰食积。
胸腹满
痛。头不痛。不恶寒。不浮紧。与伤寒异。四曰香港脚。足受寒湿。头痛身热。肢节作痛便闭
呕逆。但脚肿痛。或枯细。与伤寒异。五曰瘀血。跌触损伤。胸胁腹痛。手不可近。但头不
痛。脉不浮紧。与伤寒异。六曰内痈。发热恶寒。胸痛而咳。浊唾腥臭。右寸数大。为肺痈
。小腹重痛。便数如淋。皮肤甲错。腹皮肿急。脉滑而数。为肠痈。胃脘大痛。人迎脉盛。
胃脘痈也。但无头痛。项强。与伤寒异。
内伤外感。颇相疑混。误治必死。极当详辨。外感则人迎大于气口。内伤则气口大于人
迎。外感则寒热齐作而无间。内伤则寒热间作而不齐。外感恶寒。虽近烈火不除。内伤恶寒。得
就温暖即解。外感恶风。乃恶一切风寒。内伤恶风。惟恶些小贼风。外感症显在鼻。故鼻塞
不利。而壅盛有力。内伤症显在口。故口不知味而腹中不和。外感邪气有余。故发言壮厉。
先轻而后重。内伤元气不足。故出言懒怯。先重而后轻。外感头痛。常常而痛。内伤头痛。
时作时止。外感手背热。手心不热。内伤手心热。手背不热。若内外相兼而病者。尤当细辨
。以内症多者。是内伤重于外感。补养为先。外症多者。是外感重于内伤。解散为急。此东垣
未发之旨也。
第一种是痰证。体内停聚痰饮，出现自汗、胸部胀满，发作寒热交替的症状，但头部不痛，颈项不强硬，这与伤寒不同。第二种是食积。胸腹部胀满疼痛，头部不痛，不怕冷，脉象不浮紧，这与伤寒不同。第四种是香港脚（脚气病）。足部受寒湿侵袭，出现头痛、身体发热，四肢关节疼痛，大便闭塞，呕吐逆气，但脚部肿胀疼痛，或者枯瘦细小，这与伤寒不同。第五种是瘀血。因跌打撞击造成损伤，胸胁腹部疼痛，手不可触碰，但头部不痛，脉象不浮紧，这与伤寒不同。第六种是内痈。发热恶寒，胸痛且咳嗽，咳出浊唾腥臭之物，右寸脉数大，这是肺痈；小腹部沉重疼痛，小便频急像淋病一样，皮肤粗糙如鳞甲，腹皮肿胀紧绷，脉滑而数，这是肠痈；胃脘部剧烈疼痛，人迎脉搏动盛大，这是胃脘痈。这些病症都没有头痛、项强的表现，与伤寒不同。
内伤和外感，很容易相互混淆。误治必然导致死亡，极其应当详细辨别。外感病则人迎脉大于气口脉，内伤病则气口脉大于人迎脉。外感病则寒热同时发作而没有间歇，内伤病则寒热交替发作而不整齐。外感怕冷，即使靠近烈火也不能缓解；内伤怕冷，得到温暖即可解除。外感怕风，是害怕一切风寒之邪；内伤怕风，只是害怕轻微的小风。外感病症表现在鼻部，所以鼻塞不通利，且气息壅盛有力；内伤病症表现在口部，所以口不知味道且腹部不和。外感邪气有余，所以说话声音壮厉，先轻后重；内伤元气不足，所以说话懒弱怯懦，先重后轻。外感头痛，持续不断地痛；内伤头痛，时作时止。外感手背发热，手心不热；内伤手心发热，手背不热。如果是内外兼杂而患病的人，尤其应当仔细辨别。如果内症多者，说明内伤重于外感，以补养为先；外症多者，说明外感重于内伤，以解散为急。这是李东垣未曾阐发的旨意。
The first is Phlegm Syndrome (Tan Zheng). Retained phlegm and lingering fluid cause spontaneous sweating, chest fullness, and alternating chills and fever. However, there is no headache or stiff neck, which differs from Taiyang Cold Damage (Taiyang Shanghan). The second is Food Stagnation (Shi Ji). There is fullness and pain in the chest and abdomen, no headache, aversion to cold is absent, and the pulse is neither floating nor tight, which differs from Taiyang Cold Damage. The fourth is Hongxiang Jiao (Foot Qi / Beriberi). The feet are affected by cold-dampness, resulting in headache, body heat, pain in the limbs and joints, constipation, and vomiting/regurgitation. However, the feet are swollen and painful, or withered and thin, which differs from Taiyang Cold Damage. The fifth is Blood Stasis (Yu Xue). Caused by falls or blows, there is pain in the chest, hypochondrium, and abdomen that cannot be touched. However, there is no headache, and the pulse is not floating and tight, which differs from Taiyang Cold Damage. The sixth is Internal Abscess (Nei Yong). Fever and aversion to cold, chest pain with coughing, expectoration of turbid foul-smelling sputum, and a rapid and large right Cun pulse indicate Lung Abscess (Fei Yong). Heavy pain in the lower abdomen, frequent urination resembling strangury, skin rough like scales, abdominal wall swelling and tension, and a slippery and rapid pulse indicate Intestinal Abscess (Chang Yong). Severe pain in the epigastrium and a vigorous Renying pulse indicate Epigastric Abscess (Weiwuan Yong). These conditions lack headache and stiff neck, which differs from Taiyang Cold Damage.
Internal injury and external contraction are often confused. Misdiagnosis leads to death; therefore, careful differentiation is paramount. In external contraction, the Renying pulse is larger than the Qikou pulse; in internal injury, the Qikou pulse is larger than the Renying pulse. In external contraction, chills and fever occur simultaneously without interruption; in internal injury, they occur alternately and irregularly. External contraction causes aversion to cold that persists even near intense fire; internal injury causes aversion to cold that resolves with warmth. External contraction causes aversion to wind towards all wind-cold; internal injury causes aversion to only slight drafts. External contraction manifests in the nose, causing nasal congestion with forceful breath; internal injury manifests in the mouth, causing loss of taste and abdominal disharmony. External contraction involves excess pathogenic factors, so speech is loud and vigorous, starting soft and becoming heavy; internal injury involves deficiency of Yuan Qi, so speech is lazy and timid, starting heavy and becoming soft. External contraction headache is constant; internal injury headache comes and goes. External contraction causes heat in the back of the hand but not the palm; internal injury causes heat in the palm but not the back of the hand. If both internal and external factors are involved, careful differentiation is essential. If internal symptoms predominate, internal injury outweighs external contraction, and tonification/nourishment takes precedence. If external symptoms predominate, external contraction outweighs internal injury, and dispersing/resolving is urgent. This is the unelaborated principle of Li Dongyuan.