Section 3　Contents of the Tongue Examination

The tongue examination includes two parts: inspecting the tongue body and inspecting the tongue coating.

Inspecting the tongue body can be divided into four parts: spirit, colour, shape and motility. It is helpful for understanding the deficiency or excess of thezang-fu organs, exuberance or debilitation of the qi and blood.

Inspecting the tongue coating is separated into coating texture and coating colour. It is used to analyse the deep or superficial location of the pathogenic qi, exuberance and debilitation of pathogenic qi orzheng qi.

Inspection of the Tongue Body

1. Tongue Spirit

A. Spirited:

The tongue body is light-red, bright, with moisture, lustre and flexibility. It is called a lustrous tongue and indicates sufficient body fluids, qi and blood, and a vigourous spirit. Even if there is disease it is minor and there is little damage to thezheng (healthy) qi and belongs to a favourable manifestation.

B. Spiritless:

The tongue body is dark, dry, inflexible, and short of blood colour. It is called a withered tongue and indicates deficiency of the body fluids, qi and blood, with deterioration of the spirit; it belongs to dangerous illness and is an unfavourable manifestation.

2. Tongue Colour

Tongue colour is divided into light red, pale, red, crimson, blue and purple.

A. Light red:

Light red, moist and lustrous of the tongue body indicate harmony of qi and blood of a healthy person or the early onset of exogenous disease. The pathologic condition is mild; no injury has yet occurred to the qi, blood andzang-fu organs.

B. Pale:

If the tongue colour is lighter than normal it is called a pale tongue.

a. If the tongue is white, dry, and has nearly no blood colour; it is called dry white tongue. It is due to deficiency of qi, blood and yang. Moreover, dry white tongue corresponds to qi and blood desertion.

b. If the tongue colour is pale and the tongue body is thin; this indicates deficiency of qi and blood.

c. If the tongue colour is pale with moisture, the tongue body being fat, tender and with teeth marks on the sides of the tongue; this indicates yang deficiency and water retention.

C. Red:

Tongue colour redder than normal, even bright red corresponds to a heat pattern and can be divided into deficiency and excess.

a. Redness of the whole tongue or only red on the margins and tip of the tongue is invasion of wind-heat and belongs to exterior patterns.

b. Bright redness of the tongue indicates an excess heat pattern.

c. The tip of the tongue is red; this is caused by heart fire flaming upward.

d. The margins of the tongue are red; this is due to excessive heat in the liver channel.

e. The tongue body is thin and small, reddish, without or with less coating; this corresponds to a deficient heat pattern.

D. Crimson:

The tongue colour is darker than red. It is caused by heat entering theying and blood levels or yin deficiency resulting in vigourous fire. More redness implies more heat. A crimson tongue is hotter than a red tongue.

a. Crimson with coating indicates a warm febrile disease, heat entering theying and blood levels.

b. Crimson without coating or with less coating indicates yin deficiency resulting in vigourous fire.

E. Blue-purple:

The whole tongue appears blue or purple, it is called a blue-purple tongue. It includes light-purple tongue, purple-red tongue and crimson-purple tongue. It corresponds to inhibited movement of the qi and blood. The range of the blue-purple on the tongue body is related to the degree of the blood stasis in the body.

a. When the tongue colour is light-purple or blue-purple with moisture, this is due to deficient yang and exuberant yin or stasis of blood and channels.

b. When the tongue is red-purple, crimson-purple and lack of fluid, this is due to excessive heat damaging fluids, stagnation of qi and blood.

c. When there is a light-red tongue with a blue-purple colour, this indicates static blood in the body.

d. A blue-purple tongue can be seen in congenital heart disease or toxicities from medicines or food.

If only parts of the tongue appear with blue-purple spots, of different sizes, under the surface of the tongue, this is called stasis maculae tongue or stasis spotted tongue. In externally contracted febrile disease, it corresponds to heat entering theying and blood levels, stagnation and stasis of qi and blood, or the forerunner of macular eruption. In internal damage diseases, it is often the sign of blood stasis. Some individuals from ethnicities with darker skin often have blue-purple spots, which do not indicate any pathology and are normal.

3. Tongue Shape

The tongue shape indicates the shape and condition of the tongue body. It includes characteristics such as toughness and tenderness, being enlarged or thin, having spots, cracks, teeth-marks, etc.

A. Tough and tender:

Whether a tongue is tough or tender is the crux of distinguishing a deficiency from an excess pattern.

a. Tough tongue: The tongue body is rough and coarse, hard and sturdy. The colour is dark. This corresponds to an excess pattern.

b. Tender tongue: The tongue body is delicate, weak, slightly swollen and smooth. The colour is light. This corresponds to a deficiency pattern.

B. Enlarged and thin:

a. Enlarged tongue: The tongue body is enlarged, flabby and wide, and fills the mouth. It is indicative of stagnation of water and dampness.

If there is an enlarged tongue with light-white colour, it is due to qi and yang deficiency with retention of body fluids.

If there is an enlarged tongue with red colour, it is due to damp-heat of the spleen and stomach or accumulation of phlegm-heat.

b. Thin tongue: The tongue body is thin and small. It corresponds to deficiency of qi and blood or yin deficiency resulting in vigourous fire.

If there is a thin tongue with light colour, it is due to deficiency of qi and blood.

If there is a thin tongue with red or crimson colour, dry, without or with less coating, it is due to yin deficiency resulting in vigourous fire and damage of body fluids.

c. Swollen tongue: The tongue body is swollen, fills the mouth, possibly even with difficulty in closing the mouth or retracting the tongue. It corresponds to stagnation of heat or poisoning.

If the tongue is red-crimson with swelling and pain, it is due to excessive heat of the heart and spleen, heat toxin obstructing upward.

If the tongue is crimson-purple with swelling, it is due to excessive drinking of alcohol and contracted warm disease, the heat pathogen combined with alcohol obstructing upward.

C. Spotted:

a. Spotted tongue: The fungiform papillae are enlarged, increased in number and engorged.

b. Prickly tongue: The fungiform papillae are enlarged, protruded and forming a spike; it is thorny to the touch.

Spotted and prickly refer to the pathological characteristics of swollen or abnormal protrusion of the fungiform papillae. Spotted and prickly are often seen together, thus can be called a spotted tongue. It indicates excessive heat of thezang-fu organs or blood.

According to the colour of the spots and prickles, the conditions of qi, blood and pathological conditions can be judged. A red tongue with prickles is due to excessive heat in qi level. A bright red spotted tongue corresponds to internal-exuberance of the blood heat or yin deficiency resulting in vigourous fire. Spots and prickles that are crimsonpurple colour indicate heat entering theying and blood levels and stagnation of qi and blood.

According to the position of the spots and prickles, it can be distinguished whichzang organs the heat resides in. Spots and prickles on the tip of the tongue are due to heart fire hyperactivity. Prickles on the centre of the tongue indicate excessive heat of the stomach and intestines. Spots and prickles on the margins of the tongue indicate excessive fire of the liver and gallbladder.

D. Cracked:

There are several shapes of cracks or creases on the dorsum of the tongue. There is usually no coating found with cracks or creases. Cracks and creases are mostly caused by excessive heat, which damages the yin or spleen deficiency leading to damp encumbrance, but they can also be seen in the healthy person.

a. Pale tongue with cracks is indicative of blood deficiency and failure to moisten.

b. Red-crimson tongue with cracks is indicative of excessive heat damaging fluids or yin deficiency and dried fluid.

c. Enlarged, tender, pale tongue with cracks and teeth-marks on the margins is indicative of spleen deficiency leading to damp encumbrance.

d. If inborn shallow cracks or creases, with coating on their surface, without discomfort, this is called a congenital cracked tongue; it does not belong to an illness manifestation.

E. Teeth-marked:

The margins of the tongue are imprinted with teeth marks and are often seen with an enlarged tongue. This corresponds to spleen deficiency or exuberance of dampness. It is also seen among some healthy people.

a. A pale, enlarged and moist tongue with teeth marksmay indicate colddampness congestion or yang deficiency and water retention.

b. A light-red tongue with teeth marks on the margins may indicate spleen deficiency or qi deficiency.

c. A red, swollen tongue with teeth marks may indicate stagnation of damp-heat or phlegm-turbidity.

d. A light-red, tender tongue without being enlarged and with faint teeth marks can be seen in an inborn teeth-marked tongue. Even in illness, it is favourable.

4. Tongue Motility

Tongue motility is the active condition of the tongue body. Pathological tongue motility includes abnormal changes such as flaccidity, stiffness, trembling, deviating, protruding, waggling and shortened, etc.

A. Flaccid:

A flaccid tongue is floppy, soft and without strength, unable to extend, curl or turn naturally. It is due to yin damage or deficiency of qi and blood.

a. A flaccid tongue with red or crimson colour, without or with less coating, indicates heat pathogen damaging yin in the late stage of an exogenous heat disease or hyperactivity of fire due to yin deficiency in an interior damage disease.

b. A flaccid tongue with pale colour and without lustre indicates deficiency of the qi and blood in a prolonged illness.

B. Stiff:

The tongue body becomes stiff and unable to move, extend or retract freely. It can mostly be seen in heat entering the pericardium or fever injuring fluid, or wind-phlegm obstructing the vessels.

a. A stiff tongue with red-crimson colour, with less fluid indicates an intense heat pathogen.

b. A stiff tongue with thick and greasy coatingindicates wind-phlegm blocking the channels.

c. Sudden onset of a stiff tongue and sluggish speech, accompanied by numbness of the limbs on one side and dizziness, is the forerunner of stroke.

C. Deviated:

When the tongue is extended, it deviates to one side. This is due to liver wind with phlegm or static blood blocking the channels. This is often a sign of serious underlying pathology.

D. Trembling:

When the tongue is extended, it often quivers without stopping. It is one of the manifestations of generating wind.

a. A trembling tongue with pale colour indicates deficiency of blood generating wind.

b. A trembling tongue with red colour and less coating indicates yin fluid deficiency generating wind.

c. A trembling tongue with crimson-purple colour indicates excessive heat generating wind.

d. A trembling tongue with red-crimson colour, dizziness, and numbness of the limbs indicates liver yang transforming into wind.

E. Protruding and waggling:

A protruding tongue and waggling tongue all correspond to heart and spleen heat.

a. A protruding tongue: The tongue extends out of the mouth and is unable to be retracted immediately. Critically ill with a protruding tongue is mostly due to expiry of heart qi.

b. Waggling tongue: The patient sticks out his tongue and licks his lips, and then quickly retracts it. A waggling tongue is mostly due to excessive heat transforming into wind or seen in children with congenital mental deficiency.

F. Shortened:

a. The tongue becomes shortened and unable to extend beyond the teeth, this is a critical sign.

? If the shortened tongue is moist with pale or blue-purple colour, this may indicate cold congealing in the muscles and vessels, or deficiency of the qi and blood.

? If the shortened tongue has a red-crimson colour and is dry, this is due to heat disease damaging the fluid.

? If the tongue is shortened and enlarged, this is caused by wind-phlegm blocking the channels.

b. Ankyloglossia (Tongue-Tied): This is a congenital anomaly in which the mucous membrane under the tongue is too short, limiting the mobility of the tongue. It has no significance in pattern differentiation.

5. Sublingual Veins

Sublingual veins are the veins on the lateral sides of the lingual frenulum.

A. Method:

On curling the tip of the tongue up, either of the sublingual veins can be inspected. Inspection mainly involves assessing the changes of their length, colour, shape, etc.

B. Normal sublingual veins:

Normally the veins are appropriately raised and slender with a light-purple colour, they are not convoluted, do not have branches nor show static spots. The changes of the sublingual veins reflect the flowing conditions of the qi and blood.

C. Abnormal sublingual veins:

? If the sublingual veins are thin, short, and light-red, with obvious small vessels around them and the tongue colour is pale, this is mostly due to insufficiency of qi and blood.

? If the sublingual veins are thick, blue-purple, purple-red, crimson-purple, purpleblack, with dark-red or purple net-like small vessels, or bead-like red-purple nodules, all these are signs of blood stasis.

Inspection of the Tongue Coating

Inspection of the tongue coating includes the observation of the texture and colour of the coating.

1. Coating Texture

Coating texture means the quality and form of the tongue coating. Inspecting the coating texture includes observing whether it is thick or thin, moist or dry, greasy or curd-like, full or half covered, true or false, etc. By inspecting the coating texture, we can mainly understand the nature of the pathogen and pathogenesis of the disease.

A. Thick or thin:

The standard examination is whether it is possible to see the tongue body surface through the coating. Thick or thin mainly reflects the exuberance or debilitation of the pathogenic qi andzheng qi, and the deep or superficial location of the pathogenic qi.

a. Thin coating: through the tongue coating, one can vaguely see the tongue body. It can be seen in healthy people or in an exterior pattern, or a mild illness with an interior pattern.

b. Thick coating: through the tongue coating, one cannot see the tongue body. It corresponds to an interior pattern, such as phlegm-damp, accumulation of food, damp-heat, etc.

? If the tongue coating changes from thin to thick, it indicates gradual exuberance of the pathogenic qi and that the disease is advancing.

? If the tongue coating changes from thick to thin or a new coating is regenerating, it indicates that thezheng qi is overcoming the pathogenic qi, and the disease is relieving.

B. Moist or dry:

Moistness or dryness of the tongue coating mainly reflects the exuberance or debilitation and the transfusion or distribution of the body fluids.

a. Moist coating: the coating has moderate wetness, neither slippery nor dry. It means the normal tongue coating or body fluids are not damaged.

b. Slippery coating: the coating is watery, which is nearly dropping or dribbling when the tongue is extended. This corresponds to a cold pattern or phlegmdamp pattern.

c. Dry coating: the coating is dry and without fluid, possibly even cracked. It indicates consumption of the body fluids, interior blockage of dampness and fluids unable to go upward.

d. Rough coating: the coating is extremely dry and rough; the coarseness can feel sharp on the roof of the mouth or on the finger if it is touched. This coat is associated with a severe pattern of extreme heat damaging the fluids, or foul turbidity gathering in the middlejiao.

? If the tongue coating turns from moist to dry, it is a serious pattern of extreme heat damaging fluid, and the fluid is unable to transmit and spread.

? If the tongue coating turns from dry to moist, it may indicates the heat declining and fluid recovering, and the water pathogen begins to transform or the heat entering theying and blood levels.

C. Greasy or curd-like:

a. Greasy coating: the coating has relatively small pellets which are sticky like honey with thick fur in the centre and thin on the sides and does not disappear as being scraped or wiped. It corresponds to damp-turbidity, phlegm rheum and accumulation of food patterns.

Dirty greasy coating: the tongue coating is greasy and dirty.

Slippery greasy coating: the tongue coating is greasy, moist and slippery.

Dry greasy coating: the tongue coating is greasy, dry and with fluid deficiency.

Sticky greasy coating: the greasy coating is covered with a layer of thick mucus.

? The thick and greasy coating is mostly due to phlegm-heat, damp-heat, summer febrile disease, damp-warmth, dyspeptic retention, interior accumulation of damp phlegm, or disturbance offu qi, etc.

? The white and slippery greasy coating is due to dampness or cold-damp obstructing internally, and/or yang qi being obstructed.

? If the coating is white like powder and thick, greasy but not slippery, it is mostly due to a seasonal pathogen with internal dampness.

? If the coating is white, greasy but not dry, it is mostly due to deficiency of the spleen and heavy dampness, accumulation of food, and the qi movement being obstructed.

? If the coating is white, thick, sticky and greasy, it indicates damp-heat of the spleen and stomach with gathering pathogenic qi attacking upward.

b. Loose coating: tongue coating texture is loose. It often can be seen when the greasy and thick coating is transforming. It indicates that the pathogenic qi of damp-turbidity is being dispelled.

c. Curd-like coating: the tongue coating is thick and loose, easily scraped off. The coating grains are rough and big like being covered with a residue of soy bean curd. The base of the tongue is smooth and glossy. It corresponds to failure of the stomach qi with damp-turbidity floating upward. This is mostly due to lack of transformation of the accumulated damp-turbidity or food and belongs to the pattern of pathogenic qi in superabundance.

d. Pus or curd-like coating: there is a layer of coating just like liquid pus. It often can be seen in an interior abscess or binding of a pathogenic toxin. It is the manifestation of exuberance of the pathogenic qi and belongs to a critical illness.

e. Mouldy bean curd-like coating: there are rotten spots spreading all over the tongue like milk curds or grains of cooked rice. This is easy to be swabbed away, but regenerates suddenly. After scraping, the tongue body is left without coating. It indicates deficiency of qi and yin or mucky dampheat pathogen overflowing. It is mostly seen in seriously ill patients or malnourished children.

? If the curd-like coating fades away, and a new thin-white coating grows through, this is the result of thezheng (healthy) qi overcoming the pathogenic qi and the pathogenic qi disappearing.

? If the curd-like coating fades away, but without a new coating regenerating, it is due to debilitation of the stomach qi and belongs to rootless tongue coating.

D. Peeled:

Part or full coating peeling off. The peeled area is smooth and glossy without coating. This may indicate shortage of stomach qi, exhaustion of stomach yin or deficiency of qi and blood. It is also a sign of deficiency all over the body.

a. A peeled-like coating refers to where the peeled area is not smooth, but instead granulation or papillae can still be seen.

b. A peeled coating is divided into anterior, middle and root peeled coating, patchy peeled coating and mirror-like coating according to the location and range.

c. A geographic tongue refers to large area of peeled coating. Margins of the peeled area are prominent and the peeled area is transferable.

d. A red tongue with peeled coatingmay indicate deficiency of yin.

e. A pale tongue with peeled coating or peeled-like coating may indicate deficiency of blood, or deficiency of qi and blood.

f. A red tongue with mirror-like coating may indicate exhaustion of stomach yin.

g. A bright-white tongue with mirror-like coating may indicateying and blood depletion, expiring of yang qi.

h. A greasy and slippery, patchy peeled coating indicates deficiency ofzheng qi and damp-turbidity unable to be transformed.

The range of the peeled coating is related to the degree of deficiency of qi and yin or qi and blood. The location of the peeled coating is related to the pathological changes of thezang-fu organs. For example, peeled coating on the tip of the tongue indicates shortage of lung yin; peeled on the centre of the tongue indicates shortage of stomach yin; peeled on the root of the tongue indicates exhaustion of kidney yin.

Inspecting the changes of the tongue coating, such as growth and decline, peeled or absence can judge the existence or loss of stomach qi and stomach yin. Changes in the tongue coating also reflect exuberance or debilitation of pathogenic qi and are helpful for judging the prognosis of disease.

? The tongue coating changing from complete coverage to peeled indicates a shortage of stomach qi and yin with a gradual debilitation ofzheng qi.

? A new thin-white coating growing after the coating has been peeled indicateszheng qi dispelling the pathogenic qi or recovery of the stomach qi.

E. Waning or waxing:

a. Waning: the coating turns from thick to thin. It indicates improvement ofzheng qi and disease subsiding. But if the whole thick coating suddenly disappears, it reflects severe expiration of the stomach qi.

b. Waxing: the coating turns from thin to thick, this indicates flourishing of pathogenic qi, the disease is aggravating; but if the thin coating suddenly turns thicker, it indicates severe expiration of thezheng qi and extreme invasion of pathogenic qi.

By inspecting waning or waxing of the tongue coating, one can distinguish the prognosis of the disease. If waning or waxing happens suddenly, the prognosis will be unfavourable.

F. Full or half:

a. Full coating: the coating spreads over the whole tongue. A full coating indicates scattered pathogenic qi and is seen in phlegm-dampness obstructing the middlejiao.

b. Half coating: the coating only covers some areas of the tongue (anterior, posterior, left, right, middle or edges). This reflects accumulation of the pathogenic qi, which corresponds to the relevantzang-fu organs.

G. True or false:

Inspecting the true or false tongue coating has an important significance in the prognosis of the disease and pathogenic conditions.

a. A true coating or "tongue coating with root": the tongue coating is thick in the centre and thin on the sides, firmly attached to the tongue surface, as if growing on it and hard to scrub off. A true coating appears in the first or second stage of a disease. Thickness indicates stagnation of stomach qi or the disease is deep and critical. Prolonged disease with true coating indicates the presence of stomach qi.

b. A false coating or "tongue coating without root": the tongue coating is easily scrubbed off and resting on the surface rather than growing out of it. A false coating appears in new (acute) disease, the pathogenic condition is still mild. However, prolonged disease with a false coating indicates deficiency of stomach qi, which belongs to an unfavourable condition.

2. Coating Colour

One can differentiate the nature of a disease by inspecting the colour of the tongue coating. The tongue coating colour includes: white coating, yellow coating and grey coating; they can appear on their own or combined together.

A. White coating:

Thin-white coating: the tongue body can be seen.

Thick-white coating: the tongue body cannot be seen.

Powder-like coating: a spread of white coating like powder over the whole tongue.

A white coating may indicate an exterior pattern or a cold pattern; it can also be seen in the healthy person.

a. A thin, white and moist coating is the normal tongue coating, the beginning of the exterior pattern, a mild symptom of interior patterns, or an internal cold pattern due to yang deficiency.

b. A thin, white and dry coating may indicate a wind-heat exterior pattern.

c. A thin, white and slippery coating may indicate cold-damp due to an exterior invasion, devitalization of spleen yang or water-dampness collecting internally.

d. A white, thick and greasy coating may indicate phlegm-rheum, dampturbidity, or food accumulation.

e. A white, thick, greasy and dry coating may indicate damp-turbidity, phlegmrheum obstructing in the middlejiao with fluids not nourishing upward.

f. A powder like coating indicates warm patterns, pestilent diseases, turbiddampness with heat pathogens.

g. A cracked white coating indicates dry-heat damaging the fluid.

B. Yellow coating:

Yellow coating corresponds to a heat pattern and an interior pattern.

Light yellow coating: a light yellow colour appears steadily over a thin white coating.

Deep yellow coating: the colour is deep yellow.

A scorched yellow coating: grey and brown coatings may be classified under the yellow coating.

a. The deeper the yellow colour, the more severe the heat. A light yellow suggests mild heat, a deep yellow suggests severe heat, and a scorched yellow suggests extreme heat.

b. In an exterior disease, if the coating turns from white to yellow or white mixed with yellow, it indicates an exterior pathogen entering the interior and transforming into heat or an interior pattern mixed with an exterior pattern.

c. A thin, light yellow coating can mostly be seen in an exterior wind-heat pattern or wind-cold transforming into heat.

d. A yellow and slippery coatingcan be seen in the body with yang deficiency and cold-dampness or phlegm-rheum accumulating and transforming into heat. It also can be seen in deficiency of qi and blood with further contraction of an external pathogen.

e. A yellow rough coating, a yellow bloom on the tongue, or a scorched yellow coating, all indicate a heat pathogen damaging the body fluids, dryness accumulation and bowel excess.

f. A yellow and greasy coatingindicates internal accumulation of damp-heat or phlegm-heat or food stagnation becoming putrid.

C. Grey black coating:

Grey coating: the colour of the coating is grey or light black.

Black coating: the colour of the coating is deep grey.

A grey coating and black coating are the same classification, they differ only as to the depth of the tone. Thus, they are often both called grey black coating.

A grey black coating corresponds to severe interior heat patterns and interior cold patterns.

The degree of the colour corresponds to the severity of the heat and cold. Moistness or dryness of the coating texture is the key in judging heat or cold of the grey black coating.

A moist grey black coating corresponds to cold. A dry grey black coating corresponds to heat.