There are actually two types of high blood glucose, one is mildly elevated blood glucose that has not yet reached diabetic standards, and the other is already at diabetic levels. In mildly elevated blood glucose, most people are asymptomatic, and a very small number may have mild clinical symptoms, such as mild thirst and polyuria. When the blood glucose rises further to reach diabetes, there are again several cases. Some people remain asymptomatic and are only detected during checkups or when undergoing surgery or other unintentional findings. Most people have typical clinical symptoms, such as polyuria, polyphagia, polyphagia, and lethargy. When blood glucose rises further, or when complications occur, symptoms of complications will appear, such as nausea and vomiting in ketoacidosis, mental disorders in severe cases, blurred vision in diabetic retinopathy, edema in diabetic nephropathy, and numbness in hands and feet in diabetic neuropathy. Therefore, the symptoms of high blood glucose are not uniform, and it is important to pay attention to check when the symptoms mentioned above appear. When blood glucose is already elevated but no symptoms appear, attention should also be paid to actively intervene in all aspects to reduce various acute and chronic complications brought about by further elevation of blood glucose.