Disease-modifying therapies are available that significantly lessen the severity of the illness and accelerate the recovery in most people. Currently, plasma exchange (also known as plasmapheresis) and high-dose immunoglobulin therapy are used. Both of them are equally effective, but immunoglobulin is easier to administer. The combination of both therapies is not superior to either method. Plasma exchange is a method by which whole blood is removed from the body and processed so that the red and white blood cells are separated from the plasma, or liquid portion of the blood. The blood cells are then returned to the patient without the plasma, which the body quickly replaces. Scientists still do not understand exactly how plasma exchange works, but the technique seems to reduce the severity and duration of the Guillain-Barré syndrome episode. This may be because the plasma portion of the blood contains elements of the immune system that may be toxic to myelin.