Hemodialysis is a medical treatment used for patients with chronic kidney disease (CKD) or end-stage renal disease (ESRD). It is a process of purifying the blood of waste products and excess fluids by passing it through a machine that acts as an artificial kidney.

During hemodialysis, a patient's blood is pumped out of their body through a catheter or fistula, and then it is filtered through a dialysis machine that contains a semipermeable membrane. The semipermeable membrane separates the blood from the dialysate solution, which is a fluid that helps remove the waste products and excess fluids from the blood. As the blood passes through the membrane, waste products and excess fluids move into the dialysate, which is then disposed of.

Hemodialysis is typically performed in a hospital or a dialysis center, and it can take several hours to complete. The frequency of hemodialysis depends on the patient's specific condition, but it usually occurs three times a week. Hemodialysis is a critical treatment for patients with advanced kidney disease who require it to maintain their health and quality of life.