Some people think that diabetes is supposed to have three more symptoms, but it is not. Many diabetic patients do not have any diabetes symptoms at all and are not discovered until after a physical examination or after they have developed diabetes complications. Therefore, diabetes should be prevented as early as possible. People with the following conditions should be alert to diabetes: 1. middle-aged and elderly people over 40 years old, with reduced physical strength, depression, weakness, easy fatigue, easy to catch a cold, reduced work capacity, especially obese people. 2.Typical symptoms of diabetes, such as thirst, excessive drinking, polyuria, especially nocturnal polyuria, have appeared. 3.Unexplained weight loss with or without hyperphagia. 4.Sudden visual impairment, dark shadows in front of the eyes or uncomfortable eyes that seem to have something to paste, cataracts at a younger age or significant loss of strength. 5.Recurring boils on the body are prone to septic infection. 6.Infection with tuberculosis and rapid development of the disease. 7.Symmetrical numbness, pain or sensory allergy in the extremities. 8, Female vulva itching, recurrent vaginitis, especially mycosis fungoides. 9.Sudden myocardial infarction, or high blood pressure that cannot be controlled by medication, intractable heart failure, etc. 10.Unexplained edema or recurrent urinary tract infection. 11, lower limb ulceration or gangrene. 12.Where there is a family history of diabetes, especially twin sisters or brothers with diabetes. 13, Anyone who has a history of spontaneous hypoglycemia, especially pre-meal hypoglycemia. 14, pregnant women, especially those with a family history of diabetes, overweight and older than 25 years old; women with overdue pregnancy, fetuses over 8 pounds or a history of stillbirth. 15, women with hypomenorrhea, amenorrhea and hypersexuality, men with penile erectile dysfunction and hypersexuality.