White fur can be divided into thin and thick. Its formation, first, because the stomach gas is sucked up and condensed on the tongue; Second, Yang Qi can be inhibited due to invasion of external cold or internal cold due to yang deficiency, resulting in cold condensation on the tongue.
White fur can be normal fur, and it can also treat exterior syndrome and cold syndrome. However, due to the difference of tongue quality and fur quality, white fur has different clinical significance.
Thin and white tongue coating, red tongue, cold and heat, floating pulse, etc. It is the initial symptom of exterior syndrome and can be used as collateral evidence of exogenous diseases in syndrome differentiation. If the tongue coating is thin and white, the tongue is pale and white, and the limbs are tired and cold, it is mostly yang deficiency and internal cold syndrome; The fur is thin and dry, and the tip of the tongue is red, which is mostly caused by dryness and heat, or the heart and lungs are full of fire.
Thick white fur is thick, white, slippery or greasy, which mainly controls phlegm-dampness and turbid food resistance. If the coating is as thick as powder, it is not dry, which is caused by exogenous pollution and excessive heat toxicity, and is common in plague or carbuncle.
References:
Fundamentals of Traditional Chinese Medicine, Shanghai Science and Technology Press.