Grayish black tongue fur. Grayish black tongue fur

  Grayish black tongue fur. Grayish black tongue fur suggests severity of internal heat syndrome or internal cold syndrome. The moisture and dryness of the tongue texture are the evidences to differentiate the nature of cold and heat (see colour Fig. 16 and 17).
 
Grayish tongue fur is light-black tongue fur. So grayish tongue fur and blackish tongue fur are the same. The colour of the tongue fur corresponds to the degree of the pathological conditions. The deeper the tongue fur colour, the severer the pathological conditions. Grayish black tongue fur in cold syndrome usually develops from white tongue fur. For example, grayish black and moist tongue fur with light-white tongue signifies yang asthenia and cold exuberance, or cold dampness and internal retention of phlegm and fluid. Grayish black tongue fur in heat syndrome evolves from sallow tongue fur. For instance,grayish black and dry fur with deep-red tongue or even prickly tongue is due to extreme heat consuming fluid.