Dawn phenomenon and Somogyi phenomenon, both of which can occur in diabetic patients, both manifest as elevated fasting blood glucose in the early morning, but their pathogenesis is completely different and their treatment is diametrically opposed, so it is important to be clear. How to differentiate? Somogyi phenomenon: also called Somogyi effect, that is, having had hypoglycemia at night, which is not detected during sleep, but causes an increase in secretion of insulin antagonist hormone in the body, followed by rebound hyperglycemia after hypoglycemia. The Somogyi counter-effect itself is, for its part, a protective response of the body. Because the excitation of sympathetic nervous system and the secretion of antagonistic hormones such as adrenaline and glucagon will increase after the blood glucose is lowered, it will promote the decomposition of liver glycogen, hepatic glucose allogeneic production and myoglycogen decomposition, etc., so that the patient’s blood glucose will be restored to the basic normal range. Dawn phenomenon: That is, the blood sugar is well controlled at night and no hypoglycemia occurs, but high blood sugar only appears in a short period of time at dawn, probably due to the increased secretion of cortisol and growth hormone in the early morning; dawn phenomenon is actually a common phenomenon in diabetic patients, and it is more likely to occur when the blood sugar of diabetic patients is not so well controlled, and needs special attention. The dawn phenomenon does not occur in normal people because the secretion of insulin antagonist hormones increases at the same time as the secretion of insulin, so that blood glucose does not increase. In contrast, in diabetic patients, the increase in insulin antagonist hormone is accompanied by a defect in insulin secretion, which is unable to counteract the increase in blood glucose produced by the former and manifests as an increase in blood glucose. The best way to identify these two phenomena: It is better to have 24-hour ambulatory glucose monitoring. If there is no monitoring condition, the hospital can measure the patient’s fingertip blood glucose level several times at night and judge according to the blood glucose change curve. How to treat? The treatment measures for “Somogyi phenomenon” are: for the prevention of Somogyi phenomenon, firstly, reduce the amount of insulin (or glucose-lowering drugs) before dinner and observe the blood glucose in the morning after the reduction, if the blood glucose control becomes better and better after the reduction of insulin (or glucose-lowering drugs), it means that it is Somogyi reaction. It is more likely. This also indicates that the Somogyi reaction may be due to the use of too much insulin or too much glucose-lowering drugs, so it is the safest practice to reduce insulin (glucose-lowering drugs) to achieve the effect of reducing fasting blood sugar at breakfast. The measures to deal with the “dawn phenomenon” are: (1) a mixture of short-acting insulin and long-acting insulin before meals; (2) the addition of medium-acting insulin before dinner or bedtime. Among them, the best effect is to add medium-acting insulin before bedtime, because its peak action time can be located just before and after dawn, which can fully supplement the body’s insulin needs at dawn; (3) according to the patient’s condition, you can choose to add oral hypoglycemic drugs at night before bedtime; (4) apply insulin closed-loop pump therapy, which can automatically adjust the insulin input according to the patient’s blood sugar level. This is also the most ideal method at present, with the disadvantage that it is expensive and cannot be popularized.