Low urine output in the elderly may be caused by physiological factors, prostate enlargement, kidney disease and other factors. 1. Physiological factors: the elderly drink too little water or frequent sweating, resulting in a decrease in urine production, in urination, urine will be less, is a normal physiological performance, increase the amount of water can be returned to normal. 2. Prostatic hyperplasia: a benign lesion, when the enlarged gland presses on the posterior urethra, affecting the urine discharge, which will lead to less urination, may also be accompanied by frequent urination, urinary difficulties and other symptoms, and in severe cases, can cause urinary retention. 3. Kidney diseases: such as glomerulonephritis, nephrotic syndrome, etc., can lead to sodium retention, which will make the urine volume is relatively small, may also be accompanied by proteinuria, swelling of the lower limbs, eyelid swelling, etc., and in severe cases, can lead to renal failure or uremia. Elderly people with low urine output may also be caused by other factors, to rule out physiological factors, it is recommended to go to the regular hospital for medical examination and treatment, to avoid adverse effects.