Diabetic patients often have hypoglycemia in the process of treatment. The causes of sudden hypoglycemia in diabetic patients are as follows: First, overuse of hypoglycemic drugs. Second, the diet control is too strict or not eat normally after taking medication before meals. Some diabetic patients even do not eat breakfast after taking medication in the early morning and go out to exercise, very easy to occur hypoglycemia. Third, diabetic venereal disease, when diabetic patients are complicated with diabetic nephropathy and renal insufficiency, the drug dose should be properly reduced, otherwise it may cause hypoglycemia. Fourth, the insulin dose is not reasonable, or the irregular absorption produced by different injection sites can also cause hypoglycemia. Fifth, excessive exercise, exercise makes insulin absorption accelerate, plus the excessive consumption of glucose by exercise, which can easily cause hypoglycemia. Sixth, gastrointestinal diseases or diabetic gastric vegetative neuropathy leading to diarrhea and poor nasal function can also cause hypoglycemia in diabetic patients.