A combination of plasma exchange and dialysis, the procedure of which is easily and safely performed by our hepatic assist system, composed of a membrane plasma separator, blood and plasma pumps, hemodialyzer and controller. This may be a practical and reliable method for hepatic support at the present time, however, the results are not so satisfactory. In order to improve our system, a surfactant-free polyolefine membrane plasma separator has been developed and evaluated to be better than conventional ones in both efficiency and biocompatibility. And also, a new module of IONEX, completely saturated with heparin, has been developed as a safe and an efficient adsorbent, which selectively adsorb bilirubin and bile acids.