For patients with diabetes mellitus, poor glycemic control and persistently high blood glucose may lead to coma, a condition that often suggests the development of acute complications, most notably two: the first is diabetic ketoacidosis; the second is diabetic hyperosmolar coma. These two acute complications can have a significant impact on the patient if left untreated. Diabetic ketoacidosis is more common in young people, especially those with type 1 diabetes. This is because the patients themselves are not very clear about their own blood glucose control, not enough awareness, which may lead to a sharp increase in blood glucose in a short period of time, causing a significant decline in the efficiency of glucose utilization, metabolism through the fat and ultimately ketoacidosis, and if the ketoacidosis continues to deteriorate, metabolic acidosis will be formed. Hyperosmolar coma is more common in the elderly, because this kind of patient may have poor compliance, and the monitoring of the whole condition is not very regular, and at the same time combined with more basic diseases. In this case, if the blood sugar is persistently high, it will cause hyperosmolar coma.