The concept of therapeutic plasma exchange or plasmapheresis dates back to the beginning of this century when, in 1902, Hedon 1 bled rabbits and returned to them their washed RBCs in "artificial serum." The therapy was used in humans as early as 1909. 2 Of course, simply removing the bad blood was one of the stocks in trade of the first physicians. The Anglo-Saxon leech books appeared in the middle of the tenth century and are used to date the beginnings of medicine in England. The reasons given for performing therapeutic bloodletting a thousand years ago included many of the reasons for doing therapeutic plasmapheresis today: It eliminates rheumatic ailments, warms the marrow, promotes digestion, cleans the mind, dries up the brain, cures various sicknesses and makes the urine clean and clear. 3 The next step in the historical progression of ideas for removing ills by removing blood was the