Drinking water with sweetness in the mouth may be physiological, such as eating sweets or special thirst, etc.; it may be pathological, such as high blood sugar or digestive diseases. 1. Physiological factors: it may be related to eating sweets such as candies before drinking water, and some of the sweets remain; when you are especially thirsty, drinking water will also cause a sweet feeling; eating something with a bitter taste and then drinking water will also cause a sweet feeling. 2. Pathological factors: diabetic patients because of elevated blood sugar, will induce digestive system disorders, resulting in abnormal secretion of digestive enzymes, can also cause a sweet feeling in the mouth; digestive disorders will cause abnormal secretion of all kinds of digestive enzymes, especially the amylase content of saliva increases, can also cause a sweet feeling. It is recommended to exclude physiological factors first, and if necessary, go to the regular hospital to receive examination and treatment.