The dangers of high blood glucose include a series of symptoms such as excessive drinking, excessive eating, excessive urination, etc., affecting the patient’s daily life; prolonged elevation of blood glucose without effective control may induce complications such as atherosclerosis, diabetic foot, and renal lesions, which can seriously threaten the patient’s physical health. High blood glucose refers to a state in which the glucose concentration in the blood is higher than normal for a long period of time, which can cause a series of symptoms such as excessive drinking, excessive eating, excessive urination, weight loss, blurred vision, itchy skin and so on, affecting the patient’s daily life. In addition, long-term elevated blood glucose can also cause complications such as atherosclerosis, renal lesions, diabetic foot, etc. Atherosclerosis can induce coronary heart disease, hemorrhagic or ischemic cerebrovascular disease; renal lesions can induce chronic kidney disease, which is the main cause of end-stage renal failure; and diabetic foot can lead to deformities of the foot, skin dryness, ulcers, gangrene, and so on. Patients diagnosed with hyperglycemia should actively cooperate with the doctor’s treatment to control their blood glucose within a reasonable range, which helps to avoid a series of harms caused by high blood glucose.