《灵枢》口问∶人之自啮舌者，何气使然?曰∶此厥逆上走，脉气辈(《甲乙》作皆。)
。少阴气至，则自啮舌；少阳气至，则自啮颊；阳明气至，则自啮唇矣。《素问·阳明脉解
》∶阳明主肉，其脉血气盛，邪客之则热，热甚则弃衣而走，登高而呼；或至不食数日，反
能逾垣上屋者。四肢为诸阳之本，阳盛则四肢实，实则能登高也；热盛于身，故弃衣而走也
；阳盛则使人妄言骂詈，不避亲疏，而不欲食，故狂走也。二者证见于气，而病本于血。何
者?凡血热极，津枯而燥，则肉痒难忍，虽抓搔至血流，犹不能止，恨不刀割而针刺也；热
势稍杀，则痛作矣。夫人身之血，如胭脂然，有色有质，可粉可淖，人血亦可粉可淖者也。
其淖者，津液为之合和也。津液为火灼竭，则血行愈滞；火热既盛，则气行愈悍，血滞于前
，气悍于后。凡气之行也，前者往，后者续，以是循环无已。今则前气滞而未往，后气悍而
涌至，气气相挤，而迫于血脉之中，于是血脉之中逼迫不通，胀闷万状，其余气旁溢于细络
，更与脉外之气相逆，则皮肤之下又隐隐作痒，遂不自觉其自啮，破肉环形而不可止矣。仲
景亦谓∶持强击实，以手把刃，坐作疮也。故病有嚼舌而死者，有遍身抓搔，皮破血流，寸
无完肤，展转床蓐，气尽而死者。世皆指为冤业，孰知伤寒时病，此类极多，实为心脾血热
之所致耶!此固由邪热太亢，而由误服热药温中发汗者尤众，本承气、白虎证，而妄用四逆
、理中，势必至此矣。医者指为鬼祟，以文其过；病家认为夙业，以诬死人，岂不枉哉!事
已至此，无策可施矣。若先于势未盛时，重用石膏、大黄、生地、丹皮、栀子之属，大剂温
凉服之，犹可救也。凡患时气热病，初宜清热养液，如白芍、二冬、茅根、竹叶、石膏、知
母之类，以掣出热邪；若大便不利，证显阳明，即防热入血分，三承气不可缓也。夫血犹舟
也，津液水也。医者于此，当知增水行舟之意。叶天士所谓救阴不在补血，而在养津。即此
义也。苟不知此，妄行温补，或妄发散，则血燥而气盛，气盛则壅，壅于小络，则为啮；壅
于大经，则为狂走。其轻者壅于肌腠，亦变为瘾疹，欲出不出，而同归于死。经曰∶脉气辈
至者，骈至也。骈至，故阳盛气实，脉胀自破也。
《灵枢·口问》篇记载：人为什么会自己咬自己的舌头呢？是什么气导致的呢？回答说：这是厥逆之气向上冲走，脉气一同（《甲乙经》作“皆”）到达。少阴经气到达，就会自己咬舌头；少阳经气到达，就会自己咬脸颊；阳明经气到达，就会自己咬嘴唇。
《素问·阳明脉解》篇说：阳明经主管肌肉，它的经脉气血旺盛，邪气侵犯它就会产生热，热势严重就会让人脱掉衣服乱跑，登上高处呼喊；或者甚至几天不吃饭，反而能翻越墙头、爬上屋顶。四肢是诸阳经的根本，阳气盛则四肢充实有力，充实有力就能登高；身体热势盛大，所以脱衣奔跑；阳气盛使人胡言乱语、骂詈他人，不分亲疏，并且不想进食，所以出现狂乱奔跑的症状。这两种证候表现在气分上，但病根在于血分。为什么呢？凡是血热到了极点，津液枯竭而干燥，肌肉就会瘙痒难忍，即使抓挠到血流不止，仍然无法停止，恨不得用刀割或用针刺来缓解；如果热势稍微减弱，疼痛就会发作。
人体的血液，就像胭脂一样，既有颜色又有质地，既可以凝固成粉状，也可以化为液态。人的血液也是可以凝固或液化的。其中液化的部分，是靠津液的调和融合。如果津液被火热灼烧枯竭，血液运行就会更加停滞；火热既然旺盛，气的运行就会更加猛烈。血液在前停滞，气在后猛烈推动。凡气的运行，前面的气流过去，后面的气流接续，以此循环不已。现在却是前面的气停滞而不能前行，后面的气猛烈而涌至，前后之气相互挤压，逼迫在血脉之中，于是血脉中逼迫不通，胀闷痛苦到了极点，其余的气旁溢到细小的络脉，再与脉外的气相逆乱，那么在皮肤之下又隐隐作痒，于是就不自觉地自己咬自己，把肉咬破呈环形且无法停止。
张仲景也曾说：这是强行击打坚实之物，像手握着刀刃一样，坐着也会生出疮疡。所以有的病人因咬舌而死，有的遍身抓挠，皮破血流，没有一寸完好的皮肤，在床上辗转反侧，气绝而死。世人都把这指认为是冤孽作祟，谁知晓伤寒时行疾病中，这类情况极多，实在是心脾血热所致啊！这固然由于邪热太亢盛，而误服热药温中发汗导致这种情况的尤其众多。本来是承气汤证或白虎汤证，却胡乱使用四逆汤、理中汤，势必会发展到这种地步。医生将其指认为鬼祟，以掩饰自己的过错；病人家属认为是宿世的业障，以诬陷死者，难道不是冤枉吗！事情已经发展到这种地步，就没有办法施治了。如果在病情尚未炽盛时，重用石膏、大黄、生地、丹皮、栀子这类药物，大剂量温热凉服，还可以挽救。
凡是患时行热病的，初期适宜清热养液，如白芍、天冬、麦冬、白茅根、竹叶、石膏、知母之类，用来牵制引出热邪；如果大便不通利，证候显现出阳明病特征，就要防止热邪进入血分，三承气汤不可迟缓使用。血液就像船，津液就像水。医生在这里，应当懂得增加水量使船行驶的道理。叶天士所说的“救阴不在补血，而在养津”，就是这个意思。如果不知道这个道理，妄用温补，或妄用发散，就会导致血燥而气盛，气盛则壅滞，壅滞在细小络脉，就会表现为自咬；壅滞在大的经脉，就会表现为狂乱奔跑。轻度的壅滞在肌腠之间，也会变成瘾疹（荨麻疹），想发出来却发不出来，最终同样导致死亡。经文说：脉气骈至的，是指并排而至。因为并排而至，所以阳气盛、气实，脉道胀满自行破裂。
*Ling Shu · Kou Wen* records: Why does a person bite their own tongue? What qi causes this? It is said: This is due to *Jue Ni* (Rebellious Qi) moving upward, with the pulse qi arriving together (*Jia Yi Jing* reads "all"). When *Shao Yin* (Lesser Yin) qi arrives, one bites the tongue; when *Shao Yang* (Lesser Yang) qi arrives, one bites the cheek; when *Yang Ming* (Greater Yang) qi arrives, one bites the lips.
*Sù Wèn · Yang Ming Mai Jie* states: The *Yang Ming* channel governs the flesh, and its vessels are rich in blood and qi. When pathogenic factors invade, heat arises. Severe heat causes the patient to discard clothing and run about, climbing high and shouting; or even after several days without food, they may leap over walls and climb onto roofs. The four limbs are the root of all yang channels. When yang is excessive, the limbs become solid and strong, enabling one to climb heights. Heat overwhelming the body causes discarding clothes and running. Excessive yang leads to delirious speech, cursing others regardless of intimacy, and loss of appetite, resulting in manic running. These manifestations appear in the qi level, but the root disease lies in the blood level. Why? When blood heat reaches its extreme, fluids dry up causing dryness, muscles itch unbearably. Even scratching until bleeding occurs cannot stop it; one wishes for knife cuts or needle pricks to relieve it. If heat subsides slightly, pain ensues.
Human blood is like rouge, possessing both color and substance, capable of becoming powder or liquid. Human blood can also coagulate or liquefy. The liquefied aspect is harmonized by body fluids. If fluids are scorched and exhausted by fire, blood flow becomes stagnant. As fire-heat intensifies, qi movement becomes fierce. Blood stagnates ahead while qi surges behind. Normally, qi moves in a cycle where leading qi departs and following qi follows. Now, however, leading qi stagnates and fails to move forward, while following qi surges violently. Qi presses against qi, forcing itself into the blood vessels. Consequently, pressure within the vessels becomes obstructed, causing unbearable distension and fullness. Remaining qi spills laterally into fine collaterals, conflicting with qi outside the vessels. This causes hidden itching under the skin, leading to unconscious self-biting, tearing flesh into ring shapes that cannot be stopped.
Zhang Zhongjing also stated: This is akin to striking hard objects forcefully, or holding blades in hand, resulting in sores even while sitting. Thus, some patients die from biting their tongues; others scratch their entire bodies until skin breaks and blood flows, leaving not an inch of intact skin, tossing on bedsheets until qi exhausts and death occurs. The world attributes this to karmic retribution or demonic possession. Who knows that in cold damage and seasonal diseases, such cases are numerous, truly caused by heart and spleen blood heat! This is indeed due to excessive pathogenic heat, but even more frequently results from mistakenly administering warming herbs to induce sweating. Cases originally indicated for *Cheng Qi Tang* (Purge the Intestines Decoction) or *Bai Hu Tang* (White Tiger Decoction) were wrongly treated with *Si Ni Tang* (Frigid Extremities Decoction) or *Li Zhong Wan* (Regulate the Middle Pill), inevitably leading to this state. Physicians attribute it to ghosts to cover their errors; families attribute it to past sins to slander the dead. Is this not unjust? Once at this stage, no remedy remains. However, if before the condition peaks, heavy doses of *Shi Gao* (Gypsum Fibrosum), *Da Huang* (Rhei Radix et Rhizoma), *Sheng Di Huang* (Rehmanniae Radix), *Dan Pi* (Moutan Cortex), and *Zhi Zi* (Gardeniae Fructus) are administered in large quantities, it might still be saved.
For seasonal heat diseases, initial treatment should clear heat and nourish fluids using *Bai Shao* (Paeoniae Radix Alba), *Dong Tian* (Asparagi Radix), *Dong Bai* (Ophiopogonis Radix), *Mao Gen* (Imperatae Rhizoma), *Zhu Ye* (Bambusae Folium), *Shi Gao*, and *Zhi Mu* (Anemarrhenae Rhizoma) to draw out pathogenic heat. If bowel obstruction exists and *Yang Ming* signs appear, one must prevent heat entering the blood level; the three *Cheng Qi Tang* formulas must not be delayed. Blood is like a boat; fluids are like water. Physicians here must understand the principle of increasing water to float the boat. Ye Tianshi’s saying, "Nourishing yin does not lie in tonifying blood, but in nourishing fluids," embodies this meaning. Ignorance of this leads to reckless warming and tonification or dispersing, causing blood dryness and qi excess. Excess qi leads to congestion. Congestion in small collaterals causes biting; congestion in major meridians causes manic running. Mild congestion in muscle interstices manifests as *Yin Zhen* (Urticaria), wanting to erupt but failing, ultimately leading to death. The classic states: "Pulse qi arriving in pairs" means arriving side-by-side. Because they arrive together, yang is excessive and qi is solid, causing vessel distension and rupture.