Abstract
For the past five and a half years the HA was applied on 1632 patients with various diseases. The fundamental and clinical studies reveal that the mechanism of the efficacy of the HA can be through the improvements in hepatic cellular metabolism and RES phagocytic function. The changes in the serum osmolality gap, which is a good parameter of the middle molecular weight substances, decreased with the HA and the plasma exchange, but not with the hemodialysis. The HA should be chosen for the removal of causative substances from the patients.