The elderly do not urinate, the possible causes: 1, acute renal failure or chronic renal failure, the elderly with age, kidney function can occur natural failure, that is, the kidneys do not work, the kidneys can not effectively filter the body excess water or toxins, etc., there will be no urination. The accumulation of water and toxins in the body can cause side effects such as edema, nausea, vomiting and dizziness to occur in patients; 2. Urinary retention, common in elderly men with prostate enlargement, prostate enlargement leads to urethral obstruction, patients will have difficulty urinating, urine in the bladder and cannot be discharged through the urethra, there will be a decrease in the volume of urine or a decrease in the frequency of urination occurs, patients always have the intention to urinate, but cannot smoothly The patient always has the desire to urinate but cannot discharge smoothly; 3. Urological tumor, resulting in hydronephrosis, ureteral dilatation, urine cannot be discharged into the bladder through the obstruction site, and the patient will have reduced urine volume, and will also have back pain, lumbar sleepiness or edema and other manifestations.