Dialysis is the artificial process of eliminating waste and excessive fluid from the blood. In a healthy person, kidneys do this naturally. However, those with damaged or failed kidneys cannot perform these functions correctly, they may need dialysis.
Dialysis is basically the artificial replacement for lost kidney function. Patients become ill and have acute kidney failure (temporary loss of kidney function), or for fairly stable patients who have permanently lost kidney function (chronic kidney failure) receive dialysis treatment.