The causes of low nighttime urine volume consider the following possibilities: First, the night itself does not drink much water, get up at night and urinate less, or even do not get up at night can be observed by drinking a lot of water late at night. Second, urinary tract irritation due to inflammatory urinary tract infection, especially the occurrence of cystitis and prostatitis is more common. By drinking more water, more urination and the use of antibiotic treatment will be significantly improved. Third, the kidney function is reduced. In particular, acute and chronic renal insufficiency will appear to reduce urine. For such cases, you need to do routine urine and blood tests for kidney function to clarify. Fourth, urinary stones. Kidney or ureteral obstruction causes urinary obstruction, such cases are often accompanied by lumbar distension and pain, and even radioactive pain in the perineal area, a few patients do not have abdominal pain or lumbar pain performance can be clarified by urinary ultrasound or CT examination.