Hypoglycemia is one of the common emergencies in endocrinology. If it is not treated in time, it can even be life-threatening in serious cases. The other day, our department admitted a patient with severe hypoglycemic coma, who lived in a remote mountainous area, and had been admitted to the hospital for 11 hours since the coma was found, with the lowest blood glucose of 0.77 mmol/L. Generally speaking, if the hypoglycemic time exceeds 6 hours, irreversible damage to the brain will occur. Under our careful treatment, the patient’s eyes opened intermittently 3 days after admission, involuntary movements of the limbs appeared at 4 days, eyes were opened at 5 days, partial command movements could be completed at 9 days, involuntary speech appeared at 12 days, some commands could be understood at 13 days, and he could walk on the ground with the help of his family. 15 days later, swallowing function was restored and he could walk on his own. 18 days later, partial language function was restored. At 18 days, he regained some of his speech function. The patient has been discharged from the hospital. The patient had no previous history of diabetes, but the village doctor gave him “euglycemic” treatment after a fingertip blood glucose test of 7.8 mmol/L at the village clinic three days before admission. Euglycemia is a sulfonylurea hypoglycemic drug with a long half-life, which can easily lead to severe hypoglycemia, and is now rarely used in clinical practice. However, because of its low cost, it is still widely used in primary hospitals. Through this case, we should further understand the harm of hypoglycemic drugs to avoid unnecessary harm to patients.