Plasma taken from hepatic failure dogs induced by hepatic ischemia was used to observe the variation in its chromatogram obtained by conducting a high performance gel-chromatography (TSK G2000SW used). The progress of hepatic failure caused a distinct increase in the middle molecular (MM) fractions (m. w. over 500), which showed a good correlation with the condition of progressing hepatic failure. The reduction of the above number of peaks was observed when the hemoperfusion was performed using the polyetherurethane sheet embedded with powdered charocal (UPC) that had been newly developed mainly for the purpose of absorbing protein-bound substances. The UPC developed by the authors can successfully remove middle molecular substances in hepatic failure.