Despite substantial advances in our understanding of the pathogenesis of sepsis, the mortality of patients with severe sepsis/septic shock is unacceptably high. The potential role of extracorporeal therapies in the adjunctive treatment of sepsis is highly controversial. The present article reviews the current status of clinical research in this area. Conventional 'renal dose' continuous and discontinuous renal replacement technologies fail to achieve a biologically relevant reduction of target molecules. This may be accomplished by modified approaches, e.g. using high-dose protocols, high cut-off membranes, or (selective or unselective) adsorption techniques; however, their clinical value remains to be established by prospective studies using clinical end points.