Insulinoma is serious. Insulinoma refers to excessive insulin secretion caused by tumors in the beta cells of the pancreas. Insulin is a hypoglycemic hormone. Normally, the body decreases insulin secretion when blood sugar decreases. When blood glucose falls below 1.67 mmol/L, insulin secretion will stop. Patients with insulinoma secrete insulin autonomously and are not affected by blood glucose, so there is inappropriate overproduction of insulin in patients with insulinoma. Excessive insulin can cause the body to become hypoglycemic, and severe hypoglycemia can lead to hypoglycemic coma in patients. Persistent hypoglycemic coma can cause irreversible brain damage and even cause a vegetative state, leading to the patient’s death, so insulinoma is very serious. The diagnosis of insulinoma requires simultaneous blood sampling to measure venous blood glucose and insulin to calculate the insulin secretion index when blood glucose is below 2.8 mmol/L, and CT examination of the upper abdomen to determine the exact site of insulinoma.