According to the literature, about 30%-70%, on average 50% of diabetic patients in countries around the world do not know they have diabetes although they have had it for many years, why? Because: Type 1 diabetic patients have the typical “three more and one less” when they first get the disease, which is easy to detect early. In contrast, type 2 diabetic patients are not. When they first get the disease, their blood glucose level is mostly between 140 mg/dL and 270 mg/dL throughout the day, and they do not have the obvious “three more and one less”, so they do not go to the hospital voluntarily, but are only discovered during physical examination or examination for other diseases. Some patients are not asymptomatic but just ignore it. They are often diagnosed with diabetes because of complications such as loss of vision, edema, proteinuria, foot ulcers/impotence, periodontitis or urinary retention when they go to the hospital. Therefore, it is important to remind people that they should go to the hospital and be examined to find out if they have diabetes in the following cases: (1) People who have lost weight for which no reason can be found and whose appetite is normal. (2) Women who have given birth to a huge baby (weight >4000 grams). (3) Those who have had pregnancy complications, such as multiple miscarriages, gestational toxicity, excess amniotic fluid, fetal death in utero, or stillbirth (especially those with congenital malformations and islet cell hyperplasia found at autopsy). (4) Age over 50 years. (5) Limb ulcers that do not heal persistently. (6) Those who have a family history of diabetes over 40 years of age. (7) Obese or overweight, especially those with abdominal obesity. (8) Those with hypertension and hyperlipidemia. (9) Those who have reactive hypoglycemia. (10) Those with perineal itching, vision loss, repeated skin infections and pain or abnormal sensation in the lower extremities for which no cause can be found. Long-term treatment with diuretics or treatment with confectionary corticosteroids can lead to the disclosure of diabetes mellitus.