Cracks in a red tongue indicate Deficient Yin or Heat injuring the fluids. But if the tongue is pale and cracked, Deficient Qi or Xue is present. The tongue's coating is best described as moss or fur. It arises when the Spleen causes tiny amounts of impure substances to drift upward to the tongue. When the Spleen and Stomach are in balance, there is a uniform density of fur, with a slightly thicker area in the center of the tongue.
Thick fur indicates Excess.
Thin fur is related to Deficiency during illness, but is normal if you are well. Dry fur is a sign of Excess Yang or Deficient fluids. A greasy fur is a sign of mucous or Dampness in the body. If the fur looks peeled off or missing, it reveals Deficient Spleen or Yin or fluids. White, moist fur indicates Cold.