There are many reasons for the sweet taste in the mouth, there may be physiological factors, there may also be pathological factors, such as digestive system dysfunction, diabetes and so on. 1. Physiological factors: oral salivary amylase, the body’s normal salivary components, when people eat high starch content of food after a period of time, residual starch in the oral cavity, the starch decomposition process will be carried out to produce maltose, which will lead to the mouth sweet. Therefore, the mouth has a sweet taste, which is a normal physiological phenomenon. 2. Pathological factors (1) digestive system dysfunction: when the digestive system dysfunction, can lead to digestive enzymes in the body abnormal, when the salivary amylase content increases, can lead to saliva sugar content increases, which leads to sweet mouth, so there may be a sweet taste in the mouth. (2) Diabetes mellitus: When diabetes mellitus occurs, an increase in blood glucose levels in the body can also lead to an increase in the sugar content of saliva in the mouth, which can lead to sweetness in the mouth, and therefore a sweet taste in the mouth can occur. When there is a sweet taste in the mouth, you should seek medical attention and find out the cause in time to avoid delaying your condition.