Sweet saliva is not a characteristic symptom of diabetes because high blood glucose is metabolized mainly through urine, which results in high sugar content in urine, that is, high blood glucose is not secreted through saliva and saliva in the mouth. Therefore, diabetic patients do not have the so-called characteristic symptoms of sweet saliva. The characteristic symptoms of diabetic patients are mainly three more and one less, that is, dry mouth, excessive drinking, excessive urination, excessive eating, and unexplained weight loss, which are the most important symptoms for the early diagnosis of diabetic patients’ condition. For diabetic patients, the most crucial thing is to find out in time whether they have such a performance as three more and one less, and not to dwell on such symptoms as sweet saliva. There are many reasons for the sweetness of the mouth, and although some patients with diabetes may have the symptoms of sweetness of the mouth, it is certainly not possible to equate sweetness of the mouth with diabetes.