Thin and small tongue may be caused by lack of vitamins and trace elements, not paying attention to hygiene, impaired liver, kidney and spleen functions, genetic factors and other factors. 1. Lack of vitamins and trace elements: when the body lacks folic acid and iron, it will cause lingual inflammation, anemia, gastrointestinal dysfunction, poor growth and development and other symptoms, which will lead to the appearance of a thin tongue. 2. Lack of attention to hygiene: Lack of attention to local hygiene leads to bacteria entering into the mouth, which triggers the change of thin tongue, and in serious cases, it will be accompanied by symptoms such as fatigue, fever, sweating and so on. 3. Impaired liver, kidney and spleen function: when the liver, kidney and spleen function are impaired, the body function decreases and the toxins cannot be discharged out of the body normally, so there will be malnutrition, digestive system abnormality and other symptoms, which will lead to a thin tongue. 4. Hereditary factors: a thin tongue can also be caused by genetic factors, which can be seen in other people in the family who also have this kind of performance. If you have a thin tongue, it is advisable to go to the hospital in time to find out the cause of the disease and treat it according to the doctor’s diagnosis.