The possible causes of polyuria are as follows: 1. Diabetes mellitus, elevated blood glucose and increased plasma osmolality in diabetic patients will result in osmotic diuresis, non-stop urination, and excessive drinking or weight loss symptoms. It is recommended to go to the hospital to test fasting blood sugar to rule out diabetes. 2, urinary tract infection, the patient will appear to urinate more frequently, also will appear to increase the volume of urination, patients need to drink more to maintain the normal circulation of body fluids because of excessive urination, at the same time can be accompanied by urinary frequency, urinary urgency, painful urination and other symptoms, it is recommended to carry out routine urine examination to further confirm the diagnosis. 3, urolithiasis, patients can appear polyuria, urination volume It can be caused by central factors or peripheral target organs, such as nephrogenic enuresis. It is recommended to conduct antidiuretic hormone examination and pituitary function examination to further exclude whether the patient is suffering from enuresis.