If you, as a family member of a diabetic patient, encounter him/her in a coma, what should you do? If the blood glucose is below 2.8 mmol/L or the blood glucose meter shows “LO” (abbreviation of the English word LOW, meaning too low and cannot be measured), it indicates that the patient has low blood glucose. If you have a needle at home, you can draw 50% glucose or concentrated sugar water and inject it slowly from one corner of the mouth, make sure to prevent choking and coughing or accidental aspiration (remember never to pry open the patient’s mouth to feed sugar cubes), if you are clear, you can continue to give sugar water to feed and encourage eating, of course, it would be better if you can inject 50% glucose intravenously, and it is relatively safe to recheck the blood sugar around 10mmol/L, but make sure to Pay attention to the possibility of hypoglycemia occurring again. It is better to send the patient to the hospital; if the blood glucose shows more than 3.9mmol/L or the blood glucose meter shows “HI” (the abbreviation of the English word HIGH, meaning too high and cannot be measured), it is recommended to go to the hospital immediately to exclude the possibility of diabetic ketoacidosis, diabetic non-ketotic hyperosmolar coma or cerebrovascular accident. After seeing this article as a patient’s family members may want to learn how to check blood glucose and how to understand the meaning of the value displayed by the blood glucose meter, just in case.