唇口者，肌肉之本也。与五内相通，故观于此，可见预知其症之吉凶矣。痘毒之
发，凡唇口与舌，或紫或黑，及舌肿大者，是实热毒盛之症也。若色红活而不燥裂干红
者，是热轻而毒少也。黄白赤紫而不润泽者，凶也。至如气壮热盛，舌白至唇湿处
者，此必胃烂矣。又有唇上痘出相连，诸痘未浆，而此痘先黄熟者，则内溃已成，外痘
亦难成浆也。更有气血下陷，毒攻唇口，是以糜烂成疮，口中恶臭，牙床溃烂，舌上聚
堆黄垢，而鼻梁发红点者。又有色如干酱，其肉臭烂，一日烂一分，二日烂一寸，名曰
走马疳者，并皆不治。若痘未褪谢，而唇口干红渣滓，颊红唇紫者，此乃欲成肺痈之
候，治宜解毒清肺。若加痰喘作嗽，则以参苏饮主之。治者若得其工，此症犹堪复活
也。
夫脾之窍通于口，其华在唇，故唇口者，脾之外候也。凡疮疹发热之初，口中气
和而唇色红润者，吉。如口燥唇裂者，其毒必甚，宜急解散，否则，唇口疮出稠密，诸
疮未发而此疮先载黄浆，诸疮未收，而此疮先以焦靥，唇皮揭脱，渐变呕食呛水，昏睡
而死。若面疮肿灌，而唇上疮裂成块干溅者，重。如疮出太密，口中臭气者，此脏腑
败坏，故臭出于口也。若疮欲变坏，而唇上缩者，脾绝也。若疮下自呷者，是鱼口也。
口中涎如胶粘者，脾津竭也，并皆不治。更有唇口生疮，其声则哑者，此狐惑症也，如
不急治，多致杀人。然痘时何以又忌唇肿者？盖肿极不退，须防唇白而胃烂，痘则内
溃不出矣。何以又怕其口张者？盖张则脾败，须防气泄而惊厥发也。但因鼻塞息难，
所以张口而舒气者，不在此例。如至十朝以后，口张齿槁者，是为脾绝肾败也，不治。
唇和口，是肌肉的根本所在。它们与五脏六腑相通，因此观察唇口的变化，可以预先判断病症的吉凶。痘毒发作时，如果唇口和舌头出现紫色或黑色，或者舌头肿大，这是实热毒邪炽盛的证候。如果颜色红润鲜活且不干燥开裂、干红，说明热势较轻而毒邪较少。如果颜色黄、白、赤、紫但不润泽，预后不良（凶）。至于那些正气尚强但高热盛，舌苔白延伸至唇部湿润处的，这一定是胃壁腐烂了。又有嘴唇上的痘疹连成片，其他痘疹还未出浆，而这个痘疹先变黄成熟的，说明内部已经溃烂，外部痘疹也难以成浆。更有气血下陷，毒邪攻冲唇口，导致糜烂成疮，口中恶臭，牙龈溃烂，舌上堆积黄色垢腻，鼻梁出现红点的。还有颜色像干酱一样，肉质臭烂，一天烂一分，两天烂一寸的，名叫“走马疳”的，都属于无法治愈的绝症。如果痘疹尚未消退，而唇口干燥发红且有渣滓感，脸颊红而唇色紫的，这是将要形成肺痈的征兆，治疗应当解毒清肺。如果加上痰多气喘咳嗽，则以参苏饮为主方治疗。医生如果治疗得当，这种病症还有救活的可能。
脾的窍穴通于口，其荣华表现于唇，所以唇口是脾的外在征象。凡是疮疹发热初期，口中气息平和且唇色红润的，为吉兆。如果口燥唇裂的，其毒邪必然严重，应当紧急解表散邪，否则，唇口会生出稠密疮疡，其他疮疹未发出而此疮先结黄浆，其他疮疹未收口而此疮先焦黑凹陷，唇皮脱落，逐渐变为呕吐食物、呛水、昏睡而死。如果面部疮肿流脓，而唇上疮口裂开成块、干燥溅裂的，病情重。如果疮疹发出太密集，口中散发臭气的，这是脏腑败坏，所以臭味从口中散发出来。如果疮疹欲变坏，而唇向上缩的，是脾脏功能衰竭。如果疮口向下撕裂的，叫做“鱼口”。口中唾液像胶水一样黏稠的，是脾津枯竭，都属于无法治愈的绝症。更有唇口生疮，声音嘶哑的，这是狐惑病，如果不紧急治疗，多会导致死亡。然而为什么在痘疹期间又忌讳唇肿呢？因为肿胀极度不退，必须防止唇色发白而胃壁腐烂，痘毒就会内溃而不能外发。为什么又怕它口张不开呢？因为口张则脾败，必须防止气泄而引发惊厥抽搐。但是因为鼻塞呼吸困难，所以张口以舒缓气息的，不在此例。如果到了第十天以后，口张且牙齿枯槁的，这是脾绝肾败，无法治愈。
The lips and mouth are the root of the muscles. They connect with the five zang organs, so observing them allows one to predict the auspiciousness or inauspiciousness of the condition in advance. When the toxin of smallpox erupts, if the lips, mouth, and tongue appear purple or black, or if the tongue is swollen, this indicates a syndrome of excessive excess heat and toxicity. If the color is red and vibrant without dryness, cracking, or parched redness, it signifies mild heat and scanty toxin. If the colors are yellow, white, red, or purple but not moist and lustrous, the prognosis is ominous (inauspicious). As for cases where vital qi is strong but high fever prevails, and white coating on the tongue extends to the moist area of the lips, this must indicate rotting of the stomach. In another scenario, where pustules on the lips are connected, while other pustules have not yet formed pus, these specific pustules turn yellow and mature first; this implies that internal ulceration has already occurred, making it difficult for external pustules to form pus. Furthermore, when qi and blood sink and toxins attack the lips and mouth, leading to erosion and ulceration, foul breath, gum ulceration, accumulation of yellow greasy coating on the tongue, and red spots on the nasal bridge, the condition is severe. Another type presents with a color resembling dried paste, where the flesh rots and smells foul, deteriorating by one fen per day and one cun per two days; this is named "Zou Ma Gan" (Walking Horse Gangrene), which is incurable. If the smallpox rash has not yet faded, but the lips and mouth are dry, red, and gritty, with red cheeks and purple lips, this is a sign that Lung Abscess (Fei Yong) is about to form; treatment should focus on detoxification and clearing the lungs. If accompanied by phlegm, wheezing, and coughing, Shen Su Yin (Ginseng and Perilla Decoction) should be the primary formula. If the physician treats skillfully, this condition can still be revived.
The orifice of the Spleen connects to the mouth, and its brilliance manifests in the lips; thus, the lips and mouth are the external indicators of the Spleen. At the initial stage of fever from sores and rashes, if the breath in the mouth is harmonious and the lip color is red and lustrous, it is auspicious. If there is dry mouth and cracked lips, the toxin must be severe, requiring urgent release of the exterior; otherwise, dense sores will emerge on the lips and mouth, forming yellow pus before other sores erupt, scabbing over and becoming dark and depressed before other sores heal, with peeling lip skin, gradually progressing to vomiting food, choking on water, lethargy, and death. If facial sores are swollen and suppurating, while sores on the lips crack into blocks and become dry and splintered, the condition is heavy. If sores erupt too densely and the mouth emits a foul odor, this indicates deterioration of the zang and fu organs, causing the odor to emanate from the mouth. If the sores are about to worsen and the lips retract upward, it signifies the exhaustion of the Spleen. If sores tear downward, it is called "Yu Kou" (Fish Mouth). Saliva in the mouth that is sticky like glue indicates the exhaustion of Spleen fluids, which is also incurable. Additionally, if sores appear on the lips and mouth accompanied by hoarseness, this is Hu Huo Syndrome (Fox-Hu Syndrome); if not treated urgently, it often leads to death. However, why is lip swelling contraindicated during smallpox? Because extreme swelling that does not subside requires vigilance against white lips and stomach rot, where the smallpox toxin would ulcerate internally without emerging externally. Why is an open mouth feared? Because an open mouth indicates Spleen failure, requiring vigilance against qi leakage leading to convulsions and tetany. However, opening the mouth to breathe comfortably due to nasal congestion and difficulty breathing is not included in this category. If after ten days the mouth remains open and teeth become brittle, it signifies exhaustion of the Spleen and failure of the Kidney, which is incurable.