Dialysis is a medical procedure used to remove waste products and excess fluids from the blood when the kidneys are no longer able to perform this function effectively. There are two main types: hemodialysis, which uses a machine to filter the blood outside the body, and peritoneal dialysis, which uses the lining of the abdomen to filter blood internally. Dialysis is often necessary for patients with chronic kidney disease or acute kidney failure. It helps to maintain electrolyte balance and prevent complications associated with kidney dysfunction.