Urine volume is not necessarily a precursor to uremia, but can also be seen in physiological reasons such as low water intake, pathological reasons such as dehydration, urinary tract stones, tumors and so on. 1. Physiological reasons: if the patient drinks less water, sweating more, etc., can lead to less urine, moderate supplementation of water intake can be, without special treatment. 2. Pathologic causes: (1) dehydration: such as hemorrhage, severe vomiting diarrhea, etc., caused by insufficient blood volume, renal blood flow decreases accordingly, so it is manifested as oliguria, most of the patients in the above triggers can be restored after correction of the urine volume. (2) Urinary stones and tumors: such as ureteral stones, renal tumors, etc., obstruction occurs, urine excretion is not smooth and urine output decreases, mostly accompanied by lumbar pain, hematuria, etc. If the patient finds that the urine output becomes less, he/she will have to pay more attention to the urine output. If the patient found that the amount of urine becomes less, it is recommended to go to the regular hospital in a timely manner, improve the examination to further clarify the cause of the disease, and standardize the treatment under the guidance of the doctor.