The most common causes of hypoglycemia are insulin therapy and the use of insulinotropic sulfonylureas, especially first-generation sulfonylureas such as chlorpropamide, which are most likely to cause hypoglycemia. Postprandial hypoglycemia can occur in diabetic patients with metabolic disorders, and some patients with type 2 diabetes will show reactive hypoglycemia due to the delayed peak of insulin secretion, and the level of insulin is still relatively high 3-5 hours after meal. Diabetic patients are prone to combined kidney damage, and renal insufficiency can occur in late stages, leading to a large accumulation of insulin in the body and causing hypoglycemia. In addition, some patients with brittle diabetes with large fluctuations in blood glucose, including type I diabetes and some patients with advanced II diabetes with near-islet failure, have complete islet failure and need to rely completely on exogenous insulin for blood glucose control, while the pharmacokinetic characteristics and regulation of exogenous insulin are different from those of physiological insulin. The pharmacokinetic characteristics and regulation of exogenous insulin are significantly different from those of physiological insulin secretion, and coupled with the lack of effective auxiliary regulation in patients with advanced islet failure, the phenomenon of sudden high and low blood glucose fluctuations can easily occur. The clinical manifestation is that the patient is abnormally sensitive to insulin, and small changes in insulin dose can cause dramatic fluctuations in blood glucose.