Thin yellow tongue coating suggests that the heat is light and shallow, mostly seen in wind-heat surface evidence, or wind-cold heat into the beginning of the inside. 1. The thinness and thickness of the tongue coating mainly reflect the strength and weakness of the evil and the depth of the evil. Thin moss, mostly seen at the beginning of the disease, the evil in the surface. 2. Yellow moss, the main heat evidence, internal evidence. Because of the heat of the evil burns in the tongue, so the moss is yellow. In general, the more yellow the color of the moss, indicating that the heat is more serious, that is, light yellow moss for heat light, deep yellow moss for heat heavy, burnt yellow moss for heat knot. In addition, according to the moss yellow parts, can also distinguish the evil heat where the location of the disease, such as the tip of the tongue moss yellow, for the heat in the upper focus; tongue moss yellow, for the heat in the stomach and intestines; tongue root moss yellow, for the heat in the lower focus. If there is a thin yellow tongue, it is recommended to go to the regular hospital for diagnosis and treatment.