If the elderly have no urine for 24 hours without swelling, the cause of anuria should be clarified, which is commonly seen in pre-renal anuria, renal anuria, post-renal anuria, etc. Rehydration, diuresis, renal substitution therapy, and relief of renal ureteral obstruction can be given appropriately as the treatment plan. 1. Pre-renal anuria: some old people, suffering from serious digestive diseases such as esophageal cancer, gastric cancer and other diseases, may have violent vomiting, can not eat and drink normally, etc., in the absence of adequate rehydration, anuria will occur, at this time, it is necessary to actively treat the primary disease, intravenous rehydration to replenish water, increase blood volume, and promote the production of urine. 2. Nephrogenic anuria: some patients have normal daily water intake, but there are diseases such as acute renal failure, resulting in the loss of renal filtration function and thus causing a decrease in urine production, anuria will occur, and may not be swollen within 24 hours, generally can be treated by emergency hemodialysis and other renal replacement therapy. 3. Post-renal anuria: Some elderly people may suffer from hydronephrosis, reduced bladder voiding function and urinary retention due to prostatic hyperplasia, bilateral renal ureteral stones, etc. Usually, urine can be discharged smoothly by correcting the water-electrolyte disorders and relieving the renal ureteral obstruction. If the elderly have no urine for 24 hours, it is recommended to go to the hospital immediately, to clarify the cause of no urine, and follow the doctor’s instructions to standardize the diagnosis and treatment.