Thick and greasy white moss on the tongue may be related to dietary factors, as well as pathologies such as phlegm-damp obstruction or spleen-stomach yang deficiency. 1. Dietary factors. If the symptoms of white, thick and greasy tongue moss appear once in a while, first of all, we need to exclude the possibility of dietary factors, such as drinking milk or consuming too much yogurt products, there will be white, thick and greasy tongue moss, and can be scraped clean with a tongue scraper. 2. Phlegm-dampness obstruction. White, greasy tongue coating may also be associated with phlegm-dampness obstructing the spleen and stomach, the phlegm-dampness evil obstructing the spleen and stomach, affecting the normal function of the spleen and stomach, dampness gathered in the tongue, there will also be a pathological tongue coating performance. 3. Yang deficiency of the spleen and stomach. The deficiency of yang qi in the spleen and stomach, from which cold and dampness arise internally, affecting the transportation of water and grain essence, will also be manifested as white and greasy tongue coating. The above are the common causes of white and greasy tongue coating, when the above signs appear, you should consult a professional physician for advice on diagnosis and treatment.