Removal of protein-bound cholephilic substances such as BA by sorbent perfusion might improve the quality of life of patients with severe inoperable cholestasis where the accumulation of BA is thought to be responsible for the often distressing pruritus. Since hemoperfusion is associated with hematological side effects, plasmaperfusion which, in addition, allows the use of novel, possibly more efficient sorbents, might be preferable, provided a substance with a high affinity for these protein-bound anions could be found. A number of sorbents suitable for plasma-perfusion were therefore tested in vitro as to their BA-adsorbing capacity. U.S.P. charcoal coated onto glass beads in order to facilitate perfusion removed BA from human plasma far better than conventional charcoal suitable for hemoperfusion, charged and uncharged resins, and immobilized albumin. The extraction of BA by the coated glass beads exceeded 90% up to a load of 0.18 mumol BA per milliliter of sorbent, and the BA-adsorbing capacity was 20.8 mumol/ml. In addition to BA, the U.S.P. charcoal columns almost quantitatively removed uric acid, creatinine, and corticosteroids and retained substantial amounts of BR and thyroxine, whereas electrolytes, clotting factors, and plasmaproteins were adsorbed only initially.