The lack of taste in the mouth may be caused by digestive system diseases, mental factors, and other diseases. 1. Digestive system diseases: Digestive system diseases, such as chronic gastritis, enteritis, gallbladder stones, cirrhosis of the liver and other diseases, the above diseases will have an impact on the digestion and absorption of food, resulting in loss of appetite, the patient may feel that the mouth has no taste. 2. Mental factors: mental problems, such as anxiety, depression, schizophrenia, patients may be accompanied by different degrees of loss of appetite, resulting in tastelessness. 3. Other diseases: dry syndrome, lack of nutrition, oral infections, colds and flu, and aging leads to a gradual loss of taste, which can also lead to a lack of taste in the mouth. To summarize, there are many reasons for the lack of taste in the mouth, and it is recommended to go to the stomatology department of the hospital for examination and appropriate treatment for the primary disease.