Usually, patients who drink and urinate a lot but do not eat a lot are not necessarily diabetic. The diagnosis of diabetes mellitus needs to be made under the guidance of a professional doctor and based on clinical symptoms and test results. It is not recommended to diagnose diabetes on your own based on drinking and urinating but not eating much. Usually, patients with type 1 diabetes mellitus can have excessive drinking, urination, and eating, and most of them are accompanied by weight loss, and most of them occur at a young age, which belongs to the absolute insufficiency of diabetes mellitus insulin secretion. The diagnosis can be confirmed by fasting blood glucose measurement and glucose tolerance test, insulin release test. Type 2 diabetes mellitus patients belong to the relative insufficiency of insulin secretion, which can occur at any age, but mostly in adults, often starting after 40 years old; most of them have insidious onset of disease, with relatively mild symptoms, and more than half of them do not have any symptom; a lot of patients are found due to chronic complications, concomitant diseases, or only during health checkups. There is often a family history. It is recommended that patients with polydrinking and polyuria consult an endocrinologist for examination and treatment under the guidance of a doctor.