质紫无苔，热在阴分也。
质红无苔，热邪初入阴分，或者伤食，胃气不能上升，或忧思郁抑，阳气不能上升，须以脉
舌上无苔，质光如镜，为胃阴胃阳两伤，肠胃中之茸毛贴壁，完谷不化，饥不受食之候。亦
有顽痰胶滞胃中，茸毛不起，皆有此候。须以脉诊参断。
前症完谷阴阳伤，脉必细涩。后症痰滞，脉必洪滑而大。
质干如刺无苔，紫而干者，热伤阴液；红而干者，气不化津。须以脉诊参断。
中凹如驳去，胃有燥结伤阴，或盲肠有燥结久留不去之候。
中有直沟，如刀背印成，阴液元气皆虚也。
舌质横裂，素体阴亏也。
舌生裂纹如冰片纹，老年阴虚常见之象也。少年罕见，有此不吉。
前半光滑无苔，后根上有肉瘤二粒，如舌肉色，为阴虚痨症之象也。
表面无苔，而皮内有一块如钱大，或黄或白，为正气不足，血液亏虚，或有痰凝之候，须以
苔上见圆晕，分二三色，燥金内结，燥屎不下之候，其症必险。
苔见青绿色，必死之症也。
总之，苔黄为正，白次之，无论何症，若用药当，皆由白而黄，由黄而退，由退
复生新薄白苔，此谓顺象。无论何症，若用药不当，则由黄而白，由白而灰，由灰而黑，由活苔变为死苔，此
逆象
化苔化，气散布苔亦散布，气凝聚而结，苔亦凝聚而结
。气结于一边，苔亦结于一边。故气郁之症，苔边整齐，如石阶之起边线，线内有苔，线外
无苔，但红边而已。若气舒化则散布，
由密而疏散，则不似斩然齐一之边矣。故苔有边齐如斩者，气聚也。有积滞抑郁者也。
舌质呈紫色且无苔，表明热邪潜伏于阴分。
舌质呈红色且无苔，表示热邪刚刚侵入阴分，或者是因饮食停滞导致胃气无法上升，又或是因忧愁思虑导致气机郁结，阳气无法上升。
若舌上无苔，舌面光滑如镜，这是胃阴和胃阳同时受损的表现，肠胃中的绒毛紧贴管壁，出现完谷不化（食物未经消化即排出）以及饥饿却不想进食的症状。也有可能是顽固的痰浊胶滞于胃中，导致舌面绒毛不起，也会出现这种症状表现。必须结合脉诊来综合判断。
前述的完谷不化且阴阳两伤的情况，脉象必定细涩。后述的痰浊阻滞情况，脉象必定洪大滑利。
舌质干燥如刺且无苔，若色紫而干，是热邪损伤了阴液；若色红而干，是气机不能化生津液。必须结合脉诊来综合判断。
舌面中间凹陷，如同斑驳剥落，这是胃中有燥屎结聚损伤阴液，或者盲肠中有燥屎久留不去的症状。
舌质出现横向裂纹，是素体阴亏的表现。
舌面生出如冰片般的裂纹，是老年人阴虚常见的征象。年轻人罕见有此现象，若有则不吉利。
舌面前半部分光滑无苔，舌根处有两粒肉瘤，颜色与舌肉相同，这是阴虚劳损病症的征象。
舌表面无苔，但黏膜下有一块如铜钱大小的区域，颜色或黄或白，这是正气不足、血液亏虚，或有痰凝滞的症状，必须结合脉诊参断。
舌苔上出现圆晕，分为二三种颜色，这是燥金内结、燥屎不下导致的症状，病情必然凶险。
舌苔呈现青绿色，是必死的重症。
总之，舌苔以黄色为正象，白色次之。无论何种病症，如果用药得当，舌苔都会由白变黄，由黄消退，消退后又重新生出新的薄白苔，这称为顺象。无论何种病症，如果用药不当，舌苔就会由黄变白，由白变灰，由灰变黑，由活苔变为死苔，这称为逆象。
气化散布，舌苔也随之散布；气凝聚结聚，舌苔也随之凝聚结聚。气结在一边，舌苔也结在一边。所以气郁的病症，舌苔边缘整齐，像石阶的边缘线一样，线内有苔，线外无苔，只有红色的边缘。如果气机舒展化散，舌苔就会由密变疏，就不再像被切断那样整齐划一。因此，舌苔边缘整齐如切的，是气聚的表现，体内有积滞抑郁。
The tongue body is purple and lacks coating, indicating heat residing in the Yin aspect.
The tongue body is red and lacks coating, suggesting that pathogenic heat has just entered the Yin aspect, or it may be due to food stagnation preventing Stomach Qi from ascending, or due to worry and overthinking causing Qi stagnation and preventing Yang Qi from ascending.
If there is no coating on the tongue and the surface is smooth like a mirror, this indicates damage to both Stomach Yin and Stomach Yang. The villi within the intestines adhere to the walls, leading to symptoms of undigested food in stool (Wan Gu Bu Hua) and hunger without desire to eat. It may also be caused by tenacious phlegm stagnating in the stomach, preventing the formation of tongue coating, presenting similar signs. Pulse diagnosis must be consulted for comprehensive judgment.
In the former case of undigested food with Yin-Yang deficiency, the pulse will likely be fine and choppy (Xi Se). In the latter case of phlegm stagnation, the pulse will likely be surging, slippery, and large (Hong Hua Er Da).
The tongue body is dry and prickly, lacking coating. If it is purple and dry, it indicates heat damaging Yin fluids; if it is red and dry, it indicates Qi failing to transform into fluids. Pulse diagnosis must be consulted for comprehensive judgment.
A depression in the center of the tongue, appearing mottled or peeled, suggests dryness accumulation in the Stomach damaging Yin, or long-standing dryness accumulation in the cecum that remains unresolved.
A straight groove in the center of the tongue, resembling an imprint from the back of a knife, indicates deficiency of both Yin fluids and Yuan Qi.
Transverse cracks on the tongue body indicate a constitutional deficiency of Yin.
Cracks on the tongue resembling ice patterns are common manifestations of Yin deficiency in the elderly. This is rare in the young; its presence is inauspicious.
The anterior half of the tongue is smooth and lacks coating, while two fleshy nodules of the same color as the tongue flesh appear at the root. This is a sign of Yin deficiency consumptive disease (Yin Xu Lao Zheng).
The surface of the tongue lacks coating, but there is a coin-sized patch beneath the mucosa, colored yellow or white. This indicates insufficiency of Righteous Qi, blood deficiency, or phlegm condensation. Pulse diagnosis must be consulted for reference.
Round halos appearing on the tongue coating, divided into two or three colors, indicate internal binding of Dryness Metal and failure to pass dry feces; the condition is necessarily perilous.
Tongue coating appearing cyan-green indicates a fatal condition.
In summary, yellow coating is the normal/positive presentation, followed by white. Regardless of the disease, if treatment is appropriate, the coating will change from white to yellow, then recede, and finally regenerate as a new thin white coating. This is called a favorable pattern (Shun Xiang). Conversely, regardless of the disease, if treatment is inappropriate, the coating will change from yellow to white, from white to gray, from gray to black, and transform from a living coating to a dead coating. This is called an unfavorable pattern (Ni Xiang).
When Qi disperses, the coating disperses; when Qi condenses and knots, the coating condenses and knots. When Qi knots on one side, the coating also knots on one side. Therefore, in cases of Qi stagnation, the edge of the coating is neat, like the edge line of stone steps: coating inside the line, no coating outside the line, leaving only a red edge. If Qi relaxes and disperses, the coating becomes sparse from dense, losing its sharply cut, uniform edge. Thus, a coating with edges neat as if cut indicates Qi aggregation, associated with accumulation and depression.