The main harm of unstable blood glucose is that it affects the cardiovascular system causing peripheral vascular disease and increases the burden of kidney metabolism. The most common danger of unstable blood glucose is to cause hyperglycemia or hypoglycemia, unstable blood glucose control, which affects the therapeutic effect of drugs and causes heart burden. High blood sugar concentration in the body will cause the elasticity of blood vessels to decrease, and the inner wall of blood vessels will form atherosclerosis causing coronary heart disease. Unstable blood sugar will affect the body’s metabolism of nutrients and easily cause secondary hyperlipidemia and other diseases. Long-term fluctuations in blood glucose can easily cause a metabolic burden on the kidneys, resulting in acute renal failure, leading to the inability to excrete excess toxins from the body, thus endangering life safety.