While antibiotics address the root cause of sepsis - that of pathogen infection - they fail to provide an adequate cure for the condition. Currently, 30% to 50% of septic patients die, and this figure is likely to increase in line with the proliferation of multi-drug resistant bacteria. With an increased understanding of the immune response, it has been proposed that modulation of this defence mechanism offers the best hope of cure. Many entry-points in the immune system have been identified and targeted therapies have been developed, but why are these not in routine clinical practice? This review examines the latest evidence for the use of immuno-modulating drugs, obtained from human clinical trials. We discuss cytokine-based therapies, steroids and anti-coagulants. Finally, consideration is given as to why successful therapies in the laboratory, and in vivo models, do not automatically translate into clinical benefit.