Sepsis is a severe pathologic event, frequently causing death in critically ill patients. However, there are no approved drugs to treat sepsis, despite clinical trials of many agents that have distinct targets. Therefore, a novel effective treatment should be developed based on the pathogenesis of sepsis. We recently observed that an old hypnotic drug, bromvalerylurea (BU) suppressed expression of many kinds of pro- and anti-inflammatory mediators in LPS- or interferon-gamma activated alveolar and peritoneal macrophages (AMs and PMs). Taken the anti-inflammatory effects of BU on macrophages, we challenged it to septic rats that had been subjected to cecum-ligation and puncture (CLP). BU was subcutaneously administered to septic rats twice per day. Seven days after CLP treatment, 85% of septic rats administrated vehicle had died, whereas administration of BU reduce the rate to 50%. Septic rats showed symptoms of multi-organ failure; respiratory, circulatory and renal system failures as revealed by histopathological analyses, blood gas test and others. BU ameliorated these symptoms. BU also prevented elevated serum-IL-6 level as well as IL-6 mRNA expression in septic rats. Collectively, BU might be a novel agent to ameliorate sepsis by preventing the onset of MOF. (C) 2015 Elsevier Inc. All rights reserved.