I'm back with more on the TCM tongue. When analyzing the tongue, we mainly examine its coat, color, motility, and shape.
As for the shape/texture of the tongue - is it thin, small, rough, swollen, smooth, scalloped, fissured, mirror, or papular?
The motility of the tongue - is it rigid, flaccid, trembling, or deviated?
The color of the tongue - is it blue, purple, pale, light red, red, or dark red?
The coat of the tongue - is it black, gray, white, yellow, dry, moist, or a burnt coating?
Now, when these two components are combined, they are used to diagnose the problem the patient is suffering from. You can't take just the tongue color and determine what is going on! The entire picture of the tongue needs to be taken into consideration. Believe it or not, each of the descriptions written above, outlines a different TCM condition.
FYI: the coat of the tongue is the thin layer of saliva/fluid/mucous on the tongue. It is easiest to see first thing in the morning, before anything has been eaten or drunk, and before the teeth have been brushed. If you are going to see an ND, Acupuncturist, or TCM Doctor, they will advise you to not brush your tongue several days leading up to your appointment. Even though brushing/scraping the tongue is good to keep the mouth clean and to keep breath fresh, the coat is removed during tongue brushing/scraping and the coat is very important in a TCM diagnosis.
A bit of history on tongue diagnosis: way back when, Chinese Emperors of the Shang Dynasty would have their tongues and pulses examined before each meal. The appearance of the tongue determined what was served at the next meal, as the food was selected to treat whatever condition the tongue and pulse gave light to.