《千金》论曰∶小儿初生，先以绵裹指，拭儿口中及舌上青泥恶血，此谓之玉衡。（一作衔。）若不急拭，啼声一
发，即入腹成百病矣。《千金翼》云∶成痞病死。
《圣惠》论∶凡儿初饮乳后，以发缠指，沾清水点拭了，看齿根上有黄筋两条，便以苇刀子割断，点猪乳便瘥。
如儿口难开，但先点猪乳自开。
《小儿集验方》云∶小儿初生，每日以井华水或微温水，将洁净旧软帕子裹乳母手指，蘸水撩拭小儿口中，
因而捺舌及两颊，令稍宽舒，即不生口噤、积热、风疾等病。京畿与山东人多能之，谓之捺儿口。拭毕，仍用
少研细入麝者，干坯子胭脂涂口中，令儿美乳食。
《小儿集验方》云∶东平有一老妪，善与小儿拭口，使不生炼银。云∶小儿上下唇与齿断相连处，皆有一筋
牵引，若上唇筋紧，即生上炼；下唇筋紧，即生下炼。上炼生疮满头，或生眉间，如有癣状。瘙痒不已，时复
流出黄汁，汁至处又生疮。若下炼则起腰背，渐至四肢，亦如癣状，亦瘙痒黄汁不已。若疾盛不治，或头面上
下相通，累年不较。又咬折，或成大疾。惟是每日早晨取温水一盏，令其乳母以故软洁净帕子包手第一指，蘸
温水拭儿口，水中渲下。又拭又捺，使儿口中净，及捺上下筋，令宽舒，即小儿自美乳食，诸疾不生。亦云∶
永无炼银，惟使筋宽舒是法。京畿见小儿失捺，变为口噤不吃奶，或不解捺而生炼银者，不可胜数。
《千金方》论述说：新生儿刚出生时，先用棉团包裹手指，擦拭婴儿口腔内及舌面上的青色泥垢和恶血，这叫做“玉衡”（另一种说法叫“衔”）。如果不及时擦拭，一旦婴儿啼哭，这些污物就会进入腹部，导致各种疾病。《千金翼方》说：会导致形成痞块而病死。
《太平圣惠方》论述：凡是婴儿初次吃奶后，用头发缠绕手指，沾取清水点拭干净，观察齿根处是否有两条黄色的筋，如果有，就用苇叶刀将其割断，然后滴入猪乳汁，病就好了。如果婴儿嘴巴难以张开，可以先滴入猪乳汁，嘴巴自然会张开。
《小儿集验方》说：新生儿出生后，每天用井水第一桶水或微温水，将洁净柔软的旧帕子包裹住乳母的手指，蘸水撩拭婴儿口腔，顺便按压舌头及两颊，使其稍微宽松舒适，这样就不会发生口噤、积热、风疾等疾病。京城及周边地区以及山东人多能掌握这种方法，称为“捺儿口”。擦拭完毕后，仍需用少量研磨细的加入麝香的干坯胭脂涂抹在婴儿口中，使婴儿乳房美观且利于进食。
《小儿集验方》又说：东平有一位老妇人，擅长为婴儿拭口，使其不生“炼银”（一种唇部疾患）。她说：婴儿上下嘴唇与牙齿断开相连的地方，都有一条筋牵引着。如果上唇的筋紧绷，就会生“上炼”；下唇的筋紧绷，就会生“下炼”。上炼生在头上满头疮疡，或者生在眉间，像癣一样。瘙痒不止，时常流出黄色汁液，汁液流到的地方又生疮。如果是下炼，则起于腰背，逐渐蔓延至四肢，也像癣一样，同样瘙痒且黄汁不断。如果病情严重不治疗，或者头面部上下相通，多年不愈。再加上咬破，可能演变成大病。只有每天早晨取温水一杯，让乳母用旧的柔软洁净帕子包住手的第一指，蘸温水擦拭婴儿口腔，并将水涮下。边擦边按，使婴儿口腔干净，并按压上下筋脉，使其宽松舒适，那么婴儿自然饮食香甜，各种疾病不会发生。又说：永远不会有炼银之患，只要使筋脉宽松舒适就是方法。京城看到因未进行按压护理，导致变为口噤不吃奶，或者不懂按压而生炼银的婴儿，数不胜数。
The *Qianjin Fang* (Essential Prescriptions Worth a Thousand Gold) discusses: When a newborn is first born, one should first wrap a finger with cotton wool and wipe the blueish mud and foul blood from the infant's mouth and tongue. This is called "Yu Heng" (Jade Balance) (also known as "Xian"). If not wiped promptly, once the infant cries, these impurities will enter the abdomen and cause various diseases. The *Qianjin Yi Fang* (Supplement to Essential Prescriptions Worth a Thousand Gold) states: It leads to the formation of masses (*Pi*) and death.
The *Taiping Shenghui Fang* (Holy惠民 Formulas of the Taiping Era) discusses: After an infant takes its first feed, wrap a finger with hair, dip it in clear water, and wipe clean. Observe if there are two yellow tendons at the gum line; if so, cut them with a reed knife and apply pig milk to cure it. If the infant's mouth is difficult to open, simply applying pig milk first will cause it to open naturally.
The *Xiao'er Jiyan Fang* (Experienced Formulas for Children) states: For a newborn, every day use the first bucket well water or slightly warm water. Wrap a clean, soft old cloth around the lactating mother's finger, dip it in water, and wipe the infant's mouth. Gently press the tongue and both cheeks to make them slightly loose and comfortable. This prevents diseases such as trismus (lockjaw), accumulated heat, and wind disorders. People in the capital region and Shandong often practice this, calling it "Na Er Kou" (Pressing the Infant's Mouth). After wiping, apply a small amount of finely ground dry坯 cinnabar mixed with musk to the infant's mouth to beautify the breasts and promote feeding.
The *Xiao'er Jiyan Fang* also says: In Dongping, there was an old woman skilled at wiping infants' mouths to prevent "Lian Yin" (a specific lip disorder). She said: At the junction where the upper and lower lips connect to the teeth, there is a tendon pulling. If the tendon on the upper lip is tight, "Shang Lian" (Upper Lian) occurs; if the tendon on the lower lip is tight, "Xia Lian" (Lower Lian) occurs. Shang Lian manifests as sores all over the head or between the eyebrows, resembling tinea (ringworm). It causes incessant itching and occasionally oozes yellow fluid, which generates new sores where it flows. Xia Lian starts on the waist and back, gradually spreading to the limbs, also resembling tinea, with incessant itching and yellow discharge. If the disease is severe and untreated, or if the head and face become connected, it may persist for years without improvement. Further biting may lead to major illnesses. The method is to take a cup of warm water every morning, have the lactating mother wrap her index finger with an old, soft, clean cloth, dip it in warm water to wipe the infant's mouth, and rinse the water down. Wipe and press simultaneously to keep the mouth clean and relax the tendons above and below. Then the infant will feed well naturally, and various diseases will not arise. It is also said: There will never be Lian Yin as long as the tendons are relaxed. In the capital, one can see countless cases where infants, due to lack of pressing care, develop trismus and refuse milk, or develop Lian Yin because the pressing technique was not understood.