Glucose is one of the most important fuels for cells in our body. It is therefore essential to maintain blood glucose in a narrow range. In this lecture, normal glucose metabolism in the cells and physiological regulation of blood glucose homeostasis will be briefly reviewed. In response to hypoglycemia, counter-regulatory hormones such as epinephrine, glucagon and glucocorticoid come into play to raise blood glucose.
　　Furthermore, the pathophysiology of hypoglycemia unawareness and hypoglycemia-associated autonomic failure will be addressed.