The following are the common causes of hypoglycemia in clinical patients: 1. Diabetic hypoglycemia: Diabetic patients who use drugs that promote insulin secretion, such as sulfonylurea insulin promoters, or use insulin in excessive doses, can develop pharmacological hypoglycemia. Diabetic patients who do not eat in time, exercise excessively or drink a lot of alcohol during the application of hypoglycemic drug therapy can also cause the occurrence of hypoglycemia.2. Endocrine-related diseases: including adrenocortical insufficiency, patients can develop hypoglycemia because of the decrease of glucagon level in the body and the increase of insulin sensitivity.3. Liver-related tumor diseases: such as liver cancer, because the insulin growth factor in the body 4. Islet beta-cell tumor: Patients with islet beta-cell tumor can cause severe hypoglycemia because of increased insulin secretion in the body, especially fasting hypoglycemia can occur.