Renal failure, also known as kidney failure, occurs when the kidneys lose their ability to filter waste and excess fluids from the blood. This can lead to a buildup of harmful substances in the body, affecting overall health. There are two main types: acute renal failure, which happens suddenly, and chronic renal failure, which develops gradually over time. Symptoms of renal failure may include fatigue, swelling in the legs and ankles, and changes in urine output. Treatment options vary depending on the cause and severity, and may involve medications, dietary changes, or procedures like dialysis to help manage the condition and support kidney function.