For people with diabetes, the earlier diabetes is detected the easier it is to manage the disease to help treat it earlier. Different types and stages of diabetes have different appearances. The milder the symptoms, the more severe they can be, the more they can affect life; they can be typical or non-specific and seemingly difficult to associate with diabetes. The typical symptoms are polyuria, polydipsia, polyphagia and weight loss, which should occur in that order according to the mechanism of occurrence, but can also highlight just one symptom. Early symptoms of diabetes mellitus: Patients with diabetes mellitus do not necessarily have the typical symptoms of “three more and one less”, especially those with type 2 diabetes mellitus. Therefore, the following conditions should be suspected. (1) A family history of diabetes. People with a clear family history of mild diabetes have a high probability of developing type 2 diabetes and should be aware of it. (2) A history of abnormal childbirth. For example, a history of unexplained multiple miscarriages, stillbirths, stillbirths, premature births, malformed or giant babies, etc. (3) Recurrent infections. Those with persistent vulvar pruritus, or recurrent vulvar or vaginal mycotic infections, or repeated boils and carbuncles may have diabetes mellitus. Many female patients are found to have diabetes because they went to gynecology for vulvar itching. In addition, those with repeated respiratory, biliary, and urinary tract infections with non-healing wounds are suspected of having diabetes. (4) Impotence. Male patients presenting with impotence are suspected of having diabetes after localized lesions of the genitourinary tract have been excluded. (5) There is polyuria, thirst and excessive drinking or there is recent unexplained weight loss. (6) Occasional positive urine glucose with normal fasting glucose should also be suspected of diabetes mellitus and further examination should be performed. (7) Reactive hypoglycemia. It mostly occurs 3 hours or more after meal, manifested as panic, sweating, hunger, trembling, etc. If the blood sugar is measured, it is at or below the normal low value, and the above symptoms can disappear after eating sugar-containing food. In some obese patients with type 2 diabetes mellitus, it can be manifested early. (8) Diabetes mellitus should be suspected in young patients with arteriosclerosis, coronary artery disease, and fundus lesions. (9) When the elderly unexplained perceptual disorders, such as limb numbness, pain or sensory allergy; autonomic dysfunction, excessive sweating, especially hemiplegia, postural hypotension, unexplained urinary retention; urinary incontinence, unexplained diarrhea or alternating diarrhea and constipation; lower limb vascular lesions, such as lower limb cold, slop, intermittent claudication, extremity necrosis, blisters, ulcers, etc.; coronary heart disease myocardial infarction, renal disease, cerebrovascular accident, etc. Diabetes mellitus should be suspected in cases of myocardial infarction, renal disease, cerebrovascular accident, unexplained coma, etc. If you find any of these conditions, you should go to the endocrinology or metabolism department, or to the internal medicine department if the hospital does not have the above-mentioned specialties. If you suspect diabetes mellitus you should go to the hospital for consultation and examination. The examination includes: urine sugar, fasting blood sugar, and 2-hour postprandial blood sugar. If the diagnosis is still not confirmed, an oral glucose tolerance test can be done.