What color is the tongue moss of a bad stomach and intestines? First of all, the tongue moss is a direct reflection to the stomach qi, so the color of the tongue moss can reflect the state of gastrointestinal function. Generally speaking, when the tongue is thick and greasy, it often indicates the accumulation of dietary stagnation or the blockage of phlegm and dampness. A yellowish, thick and greasy tongue moss often indicates heat in the stomach and intestines, while a white, thick and greasy tongue moss often indicates cold in the stomach and intestines. If the tongue has little or no moss, this reflects a lack of stomach yin and stomach qi.