Anuria in the elderly is acute renal failure, anuria is the urine volume of less than 100ml in 24 hours, laboratory tests of renal function and observation of renal failure. Anuria does not mean immediate death, and normal conditions can be restored through active treatment to drain out the urine. Renal failure may be pre-renal, post-renal and renal. In pre-renal renal failure, drinking more water and replenishing the fluid volume will soon reduce the urea nitrogen and creatinine to normal. In the case of prolonged renal failure, death may occur in a week or so after anuria. If it is postrenal renal failure, by relieving the obstruction, it will soon return to normal and death will not occur immediately.