The thick and white tongue is mainly caused by the following two reasons: 1) local problems of the mouth; 2) problems of the digestive system. 1) Local problems of the mouth are mainly due to poor oral hygiene, not carefully brushing and rinsing the mouth, and not regularly going to the hospital for ultrasonic scaling, which can lead to the accumulation of food residues and bacteria in the mouth of such people, and the accumulation of too much food residues and bacteria on the surface of the tongue. 2, digestive system problems, mainly due to indigestion, stagnant food caused by the white tongue, thick, common in people who prefer to eat greasy, indigestible food, or patients have gastric ulcer, gastric dysplasia and other gastrointestinal diseases, these diseases lead to indigestion, long-term stagnant food, will also cause the white and thick tongue.