If the tongue coating is obviously white, but only a thin layer, it feels like it grew on the tongue from the beginning. If it happens once or twice occasionally, it doesn't explain the physiological problems. Just pay more attention to the cleanliness of the mouth. If this happens continuously, it may be because there is more internal heat in the body, which is a typical phenomenon of getting angry. Always pay attention to drinking more water. After the internal heat disappears, the white coating on the tongue will slowly disappear.