Thick tongue coating is mainly for the li, which may be due to qi (qi in Wei qi and Ying blood diagnosis), heat and injury to yin, qi dampness and heat, food stagnation (indigestion of food and stagnation of food in the stomach), phlegm-dampness and other conditions, which need to be combined with other symptoms to diagnose. Tongue coating is made by stomach qi fumigation in the mouth and tongue, normal tongue coating is thin white moss, if the tongue coating is thick, the following four conditions may occur: 1. Heat in the qi department injures the yin: the tongue coating is thick, yellow in color, with less fluid, accompanied by fever, thirst, large pulse, sweating and other symptoms. 2. Damp-heat in the qi division: thick, yellow tongue coating, greasy moss, accompanied by plumpness in the epigastrium (stomach and abdomen), heaviness in the limbs, fever more pronounced in the afternoon, and symptoms that cannot be relieved after sweating. 2. Food stagnation: thick tongue coating, accompanied by loss of appetite, acid swallowing (swallowing the acid in the stomach upward to the oropharynx), and sour and foul-smelling stools. 3. Internal accumulation of phlegm-dampness: see thick tongue coating, greasy texture, accompanied by symptoms such as dizziness, dark color, nausea, vomiting, easy to get tired, poor eating, sticky stools, and so on. If you feel unwell, please consult a doctor for regular treatment under his/her guidance.