Tongue diagnosis, also known as Wang She (望舌), is an important method in Traditional Chinese Medicine (TCM) for understanding the physiological functions and pathological changes of the body through the observation of tongue characteristics.
During tongue diagnosis, observations are made in the order of tip – middle – root – sides. First, examine the tongue body, then the coating, for about 30 seconds. If the initial observation is unclear, allow the patient to rest for 3-5 minutes before re-examining.
Below are some commonly encountered tongue coating illustrations compiled by the author, which we hope will be helpful.
Diagram of Tongue Diagnosis by Organ Regions
According to the Huangdi Neijing (《内经》), different parts of the tongue can reflect pathological changes in different organs, which has certain clinical reference significance. The tip of the tongue corresponds to the upper jiao (heart and lungs); the middle part corresponds to the middle jiao (spleen and stomach); the root corresponds to the lower jiao (kidneys); and the sides correspond to the liver and gallbladder.
The Shanghan Lun (《伤寒指掌 · 察舌辩证法》) also states, “The tip of the tongue belongs to the upper jiao, the middle belongs to the middle jiao, and the root belongs to the lower jiao.”
Tongue Color Section
1. Normal Tongue
The characteristics of a normal tongue are: a light red color, moist texture, moderate size, and flexibility; the coating is even, thin, white, and moist, referred to as light red tongue, thin white coating.
Normal sublingual vessels are only faintly visible, appearing as purple-red lines, and should not be swollen. Most are single branches, with the largest diameter not exceeding 2.7mm, and the length generally not exceeding 3/5 of the distance from the tongue tip to the sublingual tubercle.
2. Pale White Tongue
Pale white tongue is often seen in conditions of yang deficiency and excess cold, as well as qi deficiency and blood deficiency. This tongue appears pale white with a thin white and moist coating, indicating deficiency of both qi and blood.
3. Withered White Tongue
The tongue color and the gums and lips lack blood color, referred to as “withered white.” This tongue appears withered and dry, unable to extend, indicating decline of vital energy, critical condition.
4. Red Tongue
Red tongue is seen in conditions of external heat or yin deficiency with excess fire. This tongue appears red with a thin yellow coating and rough texture, indicating excess heat in the qi level.
5. Red Tip Tongue
Red tip tongue is often seen in conditions of heart fire rising, indicating heat in the upper jiao. This tongue has a red tip with the rest being light red and moist, indicating excess heat in the upper jiao.
6. Deep Red Tongue (1)
The deep red tongue, referred to as “scarlet tongue,” indicates excess heat. In cases of external pathogens, it signifies heat entering the nutrient level; in internal injuries with yin deficiency and excess fire, it is also commonly seen. This tongue appears deep red and dark, with leaf-like shallow cracks on the surface and little coating, indicating excess heat, stagnation of qi and blood, and damage to the righteous qi.
7. Deep Red Tongue (2)
This image is from a patient with chronic gastric fire, showing a deep red tongue with dry coating and shallow cracks on the surface, indicating internal heat blazing, gastric yin depleted, and significant damage to gastric qi.
8. Deep Red Tongue (3)
The deep red tongue has little coating, with many red spots on the anterior part (indicating fungal-like congestion), suggesting excess heat, injury to both qi and yin.
9. Cyanotic Purple Tongue
The cyanotic purple tongue is caused by poor circulation of qi and blood. This image shows a patient with chronic bronchitis complicated by infection, emphysema, and heart failure, with a dark purple tongue and white greasy coating, indicating phlegm and fluid retention, lung and kidney qi deficiency, and blood stasis.
10. Pale Purple Tongue
Pale purple tongue is often seen in conditions of yang deficiency and excess yin. This image shows a patient with pulmonary heart disease, with a pale purple tongue and thin white moist coating, indicating insufficient yang qi and poor blood circulation.
11. Pale Purple Stagnation Tongue
This image shows a patient with menstrual irregularities (dysmenorrhea), with a pale purple tongue and many purple spots, and a thin white moist coating, indicating insufficient yang qi and cold stagnation with blood stasis.
12. Purple Red Tongue
This image shows a patient with a constitution of yin deficiency, with a red tongue and little coating, due to lung infection and heart failure, with a purple-red tongue accompanied by fever and cough, indicating internal heat and stagnation of qi and blood.
13. Scarlet Purple Tongue
The tongue is scarlet and purple, with a prickly tip, indicating phlegm heat stagnation.
14. Stagnation Spots Tongue
The tongue has stagnation spots or spots, indicating blood stasis. This image shows irregularly shaped stagnation spots on the sides and edges of the tongue, indicating blood stasis in the liver channel.
Tongue Coating Section
The normal tongue coating is generated by the upward steaming of stomach qi and stomach yin, while pathological tongue coating is formed by stomach qi carrying evil qi upward. This section introduces various common tongue coating changes based on coating color and texture changes.
1. Thin White Moist Coating
This image shows a normal tongue coating. The coating is moist, and through the coating, a light red tongue body can be seen, referred to as thin white moist coating, indicating abundant stomach qi and fluid.
2. Thin White Slippery Coating
The tongue coating is excessively moist, feeling slippery and wet, and may even drip saliva when the tongue is extended, referred to as slippery coating, often due to water dampness or phlegm retention. This image shows an overly moist tongue surface, with a thin white coating, slightly thicker at the root, and a plump tongue body with tooth marks on the edges, indicating insufficient yang and internal water dampness.
3. White Greasy Coating
The greasy coating is characterized by fine and dense particles tightly adhering to the tongue surface, which do not come off when scraped, often caused by damp turbidity, phlegm retention, or food stagnation.
4. White Slippery Greasy Coating
This image shows a patient with chronic bronchitis, with a white greasy coating, excessive moisture on the tongue, pale purple tongue, and purple spots at the tip, indicating insufficient yang qi and phlegm retention.
5. White Sticky Greasy Coating
The greasy coating is covered with a layer of dirty, slippery phlegm, referred to as sticky greasy coating, indicating excess damp turbidity, with spleen and stomach yang qi being obstructed.
6. White Thick Greasy Coating
This image shows a patient with liver cirrhosis and ascites, with a pale purple tongue and thick white greasy coating in the middle, indicating yang deficiency and excess yin, with water dampness accumulating, and blood circulation stagnating.
7. White Thick Loose Coating
The tongue coating transitions from greasy to loose, with coarser particles, floating on the tongue surface, which can be scraped off, indicating recovery of yang qi, gradually transforming cold dampness and yin evil.
8. White Greasy Coating Transforming to Dry
This image shows a patient with chronic bronchitis, originally with a white thick greasy coating, now most of the greasy coating has transformed to dry, with dry cracks in the coating, indicating phlegm and fluid stagnation transforming into heat, gradually damaging stomach qi and fluids.
9. Yellow Greasy Coating Transforming to Dry
This image shows a yellow greasy coating covering the tongue surface, with the middle and front parts of the coating gradually transforming to dry, indicating internal heat blazing, with damp evil transforming to dryness.
10. Thin Yellow Coating
This image shows a patient with respiratory tract infection and fever. The tongue body is slightly red, with a thin yellow coating, indicating exterior evil entering the interior and excess heat in the qi level.
11. Yellow Greasy Coating (1)
Yellow greasy coating is often seen in conditions of damp heat, phlegm heat, food stagnation transforming into heat, summer heat, damp heat, and unbeneficial qi in the bowels. This image shows a patient after influenza, with a light yellow thick greasy coating, chest tightness, and poor appetite, indicating damp heat obstructing the middle, with spleen losing its healthy function.
12. Yellow Greasy Coating (2)
This image shows a patient with biliary tract infection, with a yellow greasy coating, indicating damp heat accumulation in the liver and gallbladder.
13. Yellow Greasy Coating (3)
This image shows a patient with liver cancer, with a red tongue and yellow thick greasy coating, with red spots on the tip, indicating obstruction of damp evil and stagnant heat.
14. Yellow Sticky Greasy Coating
This image shows a patient with intestinal obstruction, with a yellow greasy coating and a layer of yellow sticky phlegm on the tongue surface, caused by obstruction of bowel qi, with damp turbidity rising to the tongue.
15. Yellow Slippery Coating
Yellow coating can also be seen in cold damp conditions, characterized by yellow and moist coating with abundant fluid, a plump tongue body, and often pale white color, or with tooth marks on the edges, indicating yang deficiency, phlegm retention, or cold dampness.
16. Yellow Dry Coating (1)
This image shows a patient with lung infection, with the coating transitioning from white to yellow (with some white greasy coating remaining), indicating disease transforming from cold dampness to heat, with fluids being damaged.
17. Yellow Dry Coating (2)
The tongue surface is very dry, with yellow thick dry coating, rough particles, and cracks on the anterior part, indicating excess heat blazing, with fluids being depleted.
18. Yellow Petal Coating
The coating is cracked into petals, yellow and dry, with a red tongue and shallow cracks, indicating injury to fluids due to excess heat. This image still shows some white greasy coating, indicating that the original pathogenic evil was phlegm, dampness, and other yin evils.
19. Gray White Greasy Coating
The coating transitions from white greasy to gray, often seen in yang deficiency with cold dampness, phlegm retention, and other yin evils accumulating in the middle jiao, which have not transformed over time.
20. Gray Yellow Greasy Coating
This image shows a patient with pulmonary heart disease, with gray yellow greasy coating and dark purple tongue, indicating damp turbidity and phlegm heat transforming, with poor circulation of qi and blood.
21. Dirty Gray Greasy Coating
The coating is greasy and sticky, gray-yellow in color, with a layer of dirty substance on the tongue surface, referred to as dirty greasy coating, indicating excess damp turbidity.
22. Black Greasy Coating
This image shows a patient with lobar pneumonia, with the coating transitioning from white greasy to black greasy, with a red scarlet tongue and prickly tip, indicating internal heat blazing due to damp turbidity entering and transforming into fire.
23. Charred Black Coating
This image shows a patient with biliary tract infection, with a red dry tongue and black dry coating at the root, with some white greasy coating remaining, indicating excess heat and damp turbidity transforming into dryness, damaging fluids.
24. Black Dry Coating
This image was taken two days before the death of a patient with gastric cancer, showing a black dry coating, with the root covered in black coating resembling black hair, and a shriveled tongue body, indicating depletion of yin fluids and extreme internal heat.
25. Coating Shedding
Where the coating has shed, the tongue surface is smooth and devoid of coating, referred to as coating shedding, indicating deficiency of stomach yin and stomach qi, or insufficient qi and blood, failing to nourish and regenerate new coating.
26. Greasy Coating with Shedding (1)
This image shows a patient with pulmonary heart disease and heart failure, originally with a white greasy coating, now partially shed in the middle and front, with yellow-white greasy coating remaining on the sides, and a cyanotic purple tongue, indicating phlegm heat obstructing, poor circulation of qi and blood, and deficiency of stomach qi.
27. Greasy Coating with Shedding (2)
The tongue has a white thick greasy coating, with shedding, indicating phlegm dampness not transforming, stomach qi has been damaged, and the condition is mixed with deficiency and excess.
28. Map Tongue
Map tongue is a type of coating shedding, characterized by irregular patterns resembling a map, with slightly raised edges, and the location shifting over time, also caused by deficiency of stomach qi and stomach yin. It is often seen in individuals with allergic constitutions. This image shows the regrowth of new coating after treatment.
29. Mirror Tongue
The tongue has atrophied papillae, with all coating shed, resulting in a smooth surface resembling a mirror, referred to as mirror tongue, indicating depletion of stomach qi and stomach yin. It is often seen in late stages of heat illness damaging yin, internal injury with yin deficiency, and deficiency of both qi and blood. This is a red scarlet mirror tongue caused by depletion of yin fluids due to excess heat.
30. Rootless Coating (1)
The coating floats on the tongue surface, easily scraped off, and cannot regenerate new coating underneath, caused by severe damage to stomach qi and stomach yin. This image shows a patient with late-stage liver cancer, with a red scarlet tongue, yellow turbid coating, and prickly tip, indicating internal heat blazing, with severe damage to stomach yin.
31. Rootless Coating (2)
This image shows the tongue after scraping. Most of the granular yellow coating has been scraped off, with no new coating regrowth, indicating damage to stomach qi and stomach yin, with a more severe condition.
32. Thin White Coating and Yellow Thick Greasy Coating
(Thin White Coating)
(Yellow Thick Greasy Coating)
The dynamic changes in tongue appearance are significant for assessing the progression and outcome of diseases. The two images show the same patient at different times. Initially, the tongue coating was thin white, and after a few days, as the evil gradually entered the interior and transformed into heat, the coating changed to yellow thick greasy.
33. Yellow Thick Sticky Greasy Coating and Thin White Coating
(Yellow Thick Sticky Greasy Coating)
(Thin White Coating)
The yellow thick sticky greasy coating indicates a drug allergy, initially presenting as yellow thick sticky greasy coating, which has mostly retreated after treatment (as seen in the thin white coating), indicating that damp turbidity has transformed.
Tongue Lesions
1. Tongue Ulcer (1)
(Tongue Surface)
(Sublingual)
This image shows a patient with lung infection and heart failure, with a bright red tongue slightly purple, followed by white ulcerated spots on the tongue surface, some merging into patches, and spreading to other areas of the mouth, easily scraped off and quickly regenerating.
Also known as “mucosal ulceration” or “fungal coating,” it indicates injury to both qi and yin, with turbid evil rampant. It is often seen in severely ill patients with chronic conditions and weakened stomach qi. Long-term use of antibiotics, hormones, etc., can also lead to this condition.
2. Tongue Ulcer (2)
This image shows a patient with pulmonary heart disease and heart failure complicated by lung infection, with the anterior half of the tongue coating shed due to prolonged illness, and white curd-like substances appearing on the tongue surface. The prognosis is poor.
3. Tongue Sores
One or more superficial yellow-white ulcers appear on the tongue, surrounded by congestion and causing pain, referred to as “tongue sores.” This condition occurs intermittently and is often caused by excess fire from yin deficiency, heart fire, excessive stomach heat, qi deficiency, or yang deficiency. It is easily triggered by fatigue.
4. Heavy Tongue
The sublingual blood vessels are swollen, resembling a small tongue growing on the main tongue, referred to as a heavy tongue. This is often caused by heart fire rising or external evil stirring heart fire.
5. Tongue Cancer
Fungal-like malignant growth appears on the edge of the tongue, with ulceration and severe pain, accompanied by extremely foul saliva. This is caused by heart and spleen fire stagnation, qi stagnation, and is classified as a malignant lesion of the tongue.6. Tongue Papilloma
A yellow bean-sized growth appears on the tongue, painless, not ulcerated for a long time, growing very slowly, with a better prognosis.
7. Tongue Hemangioma
This image shows a congenital tongue hemangioma. There is a swelling on the tongue, slightly purple in color, with no discomfort. This is caused by stagnation of blood vessels in the tongue, with no diagnostic significance, and should be differentiated from a swollen purple tongue.
8. Tongue Ulcer (Tongue Cancer)
This condition commonly occurs on the middle to posterior edges of the tongue, initially presenting as a small ulcer on the edge, gradually enlarging, causing pain that hinders eating, and if ulceration and blood vessels are involved, it can lead to severe bleeding.
9. Tongue Bleeding
Bleeding from the tongue is referred to as “tongue bleeding.” It can be caused by heat stagnation in the heart, deficiency fire in the spleen and kidneys, etc. Generally, bleeding caused by excess fire is more profuse, often accompanied by swelling and pain of the tongue; bleeding caused by deficiency fire is more likely to be seen as oozing blood without swelling of the tongue. It can also be caused by qi not holding blood.