Blood glucose fluctuates from high to low in the treatment of diabetic patients is a frequent phenomenon, in fact, it can also occur in the normal population, because blood glucose and blood pressure are constantly changing, and is affected by many factors, such as mental, emotional, exercise, diet, drugs, etc.. The common reasons are as follows: 1. Irregular diet, irregular meal time, irregular amount of food and overeating can lead to blood sugar fluctuations. 2. Emotional changes, such as excitement, agitation, sadness and grief, can lead to blood sugar fluctuations. 3. 4.Inappropriate use of insulin or hypoglycemic drugs, especially sulfonylureas, may lead to a significant drop in blood glucose, and after the drop in blood glucose, rebound hyperglycemia may occur, followed by sudden high and low blood glucose. 5.After gastrointestinal surgery, the food eaten cannot be digested and absorbed in the stomach, but directly enters the jejunum, resulting in rapid absorption of glucose, increased blood glucose, stimulating insulin secretion, and causing a rapid drop in blood glucose. For type 1 diabetic patients, their pancreatic function is poor, and it is very easy to have high and low blood sugar and fluctuation. Therefore, there are many reasons for high and low blood sugar, so it is important to avoid triggers and keep blood sugar stable.