Library

Any method that distinguishes the five Zang organs based on the five colors of the tongue coating is a rigid and dead approach within the Five Elements theory, insufficient for measuring the complex changes in symptoms caused by miscellaneous infections across the four seasons. Only by observing the white, yellow, gray, and black colors of the tongue coating, and the red, crimson (Jiang), purple, and cyan colors of the tongue body, to examine the symptomatic manifestations of the Six Meridians transmission (the progression of disease among the six meridians), can one be absolutely reliable, having been verified repeatedly without error. The key for physicians to grasp diagnosis relies primarily on this.

Regarding the coating on the tongue, which appears as turbid and floating, regardless of whether it is white, yellow, gray, or black, one must first distinguish between dryness and moisture, and whether it is hard or loose when scraped, to determine the deficiency or excess of fluids in the stomach and intestines. This is a crucial principle. If there is no coating but the tongue color changes, it mostly belongs to deficiency syndromes of the Heart and Kidney, or syndromes of Wind-Fire blazing in the Liver and Gallbladder, and even to critical syndromes of exhaustion of Zang organ Qi. At this point, one must carefully observe the vitality ("Shen") of the tongue color and the flourishing or withered state of the tongue texture, distinguishing whether the true Qi of the Zang organs is exhausted or not, thereby determining life or death in complicated or deteriorating conditions. This is also a most crucial principle.

When touching the tongue with hand, if it feels slippery and soft, the disease belongs to Yin syndromes; if it feels rough and coarse, the disease belongs to Yang syndromes, which is already known. However, although tongues in deficiency-cold syndromes are indeed slippery and soft, in cases where pathogenic factors initially transmit to the interior, and in True Heat False Cold syndromes, slippery and soft tongues may occasionally appear. Although tongues in excess-heat syndromes are indeed rough and coarse, in cases of blood deficiency and fluid depletion, and in True Cold False Heat syndromes, rough tongues may also occur. The distinction lies in: For deficiency-cold syndromes, the entire tongue is pale white, slippery, and tender, with no extra coating, no red spots, and no cracks. For syndromes where pathogens initially transmit to the interior, the entire tongue is white and slippery with a floating and greasy coating. For cold stagnation accumulating in the middle Jiao, the tongue appearance is similar. For True Heat False Cold syndromes, the entire tongue is white but has red spot patterns, cracks, and various solid coatings like sand accumulation, and the coating on the tongue cannot be completely scraped off, while the color under the tongue often hides redness. If scraped heavily, a small amount of bleeding may occur beside the sand points. For excess-heat syndromes, and syndromes where pathogenic fire enters the Yin meridians, the entire tongue must have yellow or black coatings, presenting characteristics such as accumulation, dryness, scorching, cracking, and prickles. For blood deficiency and fluid depletion syndromes, the entire tongue must be crimson without coating, or have horizontal and vertical cracks, and the tongue may be short and small. For True Cold False Heat syndromes, although the entire tongue may have gray-black coatings that are dry, rough, scorched, cracked, and thick with prickles, these coatings are loose and floating, not reaching the edges, and can be wiped off cleanly with light friction; the base of the tongue must be pale white and not red, or pale red with a round, large, fat, and tender tongue. This is the flexible principle for distinguishing cold and heat through tongue observation.

Tongue shortening due to congenital reasons is unrelated to longevity and has no curative medicine. If shortened due to illness, it indicates pathogens sinking into the Three Yin meridians (Taiyin, Shaoyin, Jueyin), all capable of causing tongue shortening. One should first distinguish the coating color. If the tongue is red and short with white blisters, it indicates Shaoyin blood deficiency with hyperactive fire, suitable for nourishing Yin and descending fire. If the tongue is black and short with dry, scorched coating, it indicates extreme heat in Jueyin forcing fire, suitable for urgent purgation to preserve Yin, with a chance of saving two or three out of ten. Only when the tongue is short and curled, accompanied by retraction of the testes in men and breasts in women, does it indicate extreme heat in the Zang and Fu organs and exhaustion of Liver Yin, which is mostly untreatable; however, if the patient can tolerate large doses of clearing, moistening, and purgative medicines, one or two out of ten might be saved. Regarding tongue stiffness, it is divided into strong tongue, wooden tongue, double tongue, swollen tongue, and large tongue. Strong tongue mostly occurs in Phlegm-Heat syndromes; wooden tongue and double tongue mostly occur in Dry-Heat syndromes of the Heart meridian; swollen tongue and large tongue mostly occur in Damp-Heat syndromes of the Spleen meridian. All belong to excess-heat syndromes, without deficiency-fire, with Heart meridian blood-heat being the most common. This is the general principle for distinguishing short and stiff tongues.

When observing the tongue coating, yellow coating is easy to identify but appears only in exterior-interior excess-heat syndromes, rarely in exterior-interior deficiency-cold syndromes. Exterior syndromes involving Wind, Fire, Summer-heat, and Dryness all have yellow coating; in Shanghan (Cold Damage) diseases, the coating turns yellow only after pathogens transmit to the interior and enter the Stomach. Black coating always belongs to interior syndromes, never exterior syndromes, and can appear in cold, heat, deficiency, and excess syndromes. There are also false coatings caused by smoking or food staining, which are harder to distinguish. Gray coating is black mixed with purple, appearing in excess-heat syndromes, not deficiency-cold syndromes; it appears in damp-heat transmitting to interior syndromes, epidemic plague syndromes, phlegm stagnation in the chest syndromes, and blood stasis with mania syndromes. These symptoms vary. If it is pale gray or pale black, black mixed with white, it mostly indicates cold damaging the Spleen and Kidney. Mustard-jelly coating is yellow-red mixed with black, appearing in cases of long-standing internal heat stagnation, food-stagnation summerheat stroke, and food-stagnation Shanghan transmitting to the Spleen. Regardless of symptoms and pulse, it belongs to excess-heat interior syndromes, without exterior deficiency-cold syndromes. White coating is particularly complex and difficult to diagnose, appearing in exterior-interior cold-heat deficiency-excess syndromes, often mixed with other colors or changing colors, with combined syndromes and half-exterior-half-interior syndromes, requiring detailed differentiation. In summary, when observing coating color, one must first distinguish the condition after scraping. If the tongue is slippery and smooth after scraping, with no turbidity, and the base shows pale red and luster, it belongs to rootless floating coating, mostly indicating exterior, deficiency, or cold syndromes. If it cannot be scraped clean, or after scraping off the turbidity, a dirty substance remains on the tongue base, thin like paste, greasy and涩 (astringent) without fresh redness, it belongs to rooted true coating, mostly indicating interior, excess, or heat syndromes. Next, distinguish the presence of cinnabar red spots, cracks, and prickles, and whether the coating is tightly adhered or loose and floating. Initial changes from white to yellow, yellow to gray to black, or yellow-black to mustard-jelly, with coating starting in the center and extending to the root and tip, accompanied by red spots, prickles, and cracks, and tightly adhered without looseness, all belong to interior, excess, and deteriorating heat syndromes. If suddenly turning from pale white slippery coating to gray or black, without passing through a yellow stage, appearing scorched black with prickles and cracks at first glance, but scraping clean and becoming moist when wetted, without red spots or cracks, and with a floating and puffy shape, all belong to the false coating of True Cold False Heat. This is the general principle for distinguishing exterior-interior cold-heat deficiency-excess through coating color.

Regarding tongue color, a whole tongue that is pale red, neither shallow nor deep, indicates a healthy person. Any deviation indicates disease. Red tongue appears in exterior, interior, deficiency, excess, and heat syndromes, but not in cold syndromes. Although red tongue generally indicates heat, there are distinct variations such as red and thin, red and flaccid, red and short, red and stiff, red with star points, red with dots, red trembling, red circles, red cracks, and red fragmentation. One must combine current symptoms to clearly differentiate. Purple tongue appears in exterior-interior excess-heat syndromes, not deficiency-cold syndromes. Although caused by various factors such as cold transforming into fire, internal onset of warm epidemics, alcohol and food damp-stagnation, or mistaken use of warming and tonifying medicines, it always belongs to Liver collateral heat syndromes. If pale purple is mixed with other colors, there may also be deficiency-cold syndromes. Cyan tongue mostly indicates bad omens rather than good ones. If cyan and slippery with thin coating, it mostly indicates cold damaging the Liver, treatable with warming medicines. For women with fetal death in the uterus, purgative medicines can also be used for rescue. If pure cyan without coating and shiny, the vital Qi of the Zang and Fu organs is exhausted, definitely fatal and untreatable. If pale red tongue shows blue streaks, it indicates cold-food stagnation in the Stomach, treatable with urgent warming and tonifying or warming and unblocking medicines. This is the general principle for distinguishing cold-heat deficiency-excess and auspicious/inauspicious life/death through tongue color.

In conclusion, examining the tongue to judge symptoms initially makes no distinction between men, women, old, and young. Although observing the tongue visually provides more evidence than palpating the pulse, one must still investigate the disease source, clearly differentiate current symptoms, and inquire about the patient's constitutional type (Yin Zang, Yang Zang, or Ping Zang) to adapt flexibly and prescribe appropriate medicines, ensuring warming, cooling, tonifying, and purging are balanced without bias. Prudence regarding the eight characters of Exterior, Interior, Yin, Yang, Cold, Heat, Deficiency, and Excess, with accurate differentiation, allows for the subtle application of adapting to constant changes and following principles. If one does not clarify the disease source and symptoms beforehand, claiming that tongue signs are real unlike the illusory nature of pulses, and using trial-and-error medicines with presumptuous endorsement, asserting specific medicines cure specific tongues, it leads to many errors. Future students must be careful and cautious.

[Commentary by Rongzhai] Tongue examination is a powerful aid in Inspection (Wang Zhen). Therefore, any changes in blood regulation (e.g., blood heat causes red tongue with nodular edges, blood stasis-heat causes crimson and purple tongue) and the abundance or scarcity of body fluids (e.g., flourishing and moist indicates sufficient fluids, dry and withered indicates fluid deficiency, or withered like an oil-soaked kidney) have physical manifestations to verify; and the coating/turbidity is the most significant part reflecting digestive system pathology. Zhang Xugu said: "Observing the tongue body verifies the Yin-Yang and deficiency-excess of Zheng Qi (Upright Qi); examining the coating reveals the cold-heat and superficial-deep nature of Xie Qi (Pathogenic Qi)." This is the major method for observing tongue and coating. Further speaking: If the disease is excess, the tongue must be firm, tight, and aged/coarse; if the disease is deficiency, the tongue must be floating, puffy, and delicate/tender. Using this for differentiation, whether it is deficiency or excess, true or false, one can understand the general situation even without combining symptoms and pulse taking. Once deficiency and excess are distinguished, the tonifying and purging of medicines naturally follow fixed laws. However, deficiency and excess each have Yin and Yang aspects, and tongue body and tongue color also have distinctions. For example: In Yin deficiency with Yang hyperactivity, the tongue must be dry; in Yang deficiency with Yin hyperactivity, the tongue must be slippery; in Yin deficiency with Yang hyperactivity and hyperactive fire, the tongue must be dry and parched; in Yang deficiency with Yin hyperactivity and deficient fire, the tongue must be slippery and wet. Such differentiation makes Yin/Yang and deficiency/excess clearly visible."