Hemodialysis is a medical treatment used to filter waste and excess fluids from the blood when the kidneys are not functioning properly. During the procedure, blood is drawn from the body and passed through a machine called a dialyzer, which acts as an artificial kidney. The dialyzer removes toxins and excess substances before returning the cleaned blood to the body. Typically, hemodialysis is performed three times a week, with each session lasting about three to five hours. Patients may receive treatment in a dialysis center or at home, depending on their specific needs and health conditions.