Objective To investigate the effects of ulinastatin on serum concentrations of advanced oxidation protein products and C-reactive protein in patients with multiple organ dysfunction syndrome(MODS).Methods Seventy-two patients with MODS were randomly divided into ulinastatin group(n=36) and control group(n=36).The serum concentrations of advanced oxidation protein products and C-reactive protein in two groups were determined before therapy and after 3d,5d and 7d of therapy.Acute physiology and chronic health evaluation Ⅲ (APACHE Ⅲ)for patients were recorded before therapy and after 3d,5d,7d of therapy.Mortality within 28d was also compared between the two groups.The serum concentrations of advanced oxidation protein products and C-reactive protein in 36 healthy volunteers were detected as normal control.Results The concentrations of AOPP and CRP in patients with MODS before therapy were significantly higher than those obtained from healthy volunteers(P<0.05), whereas no obvions difference was found between the two groups.However,the levels of AOPP and CRP in patients with MODS were significantly decreased after 3d,5d,7d of therapy.Compared with control group,AOPP concentrations and CRP levels were markedly attenuated and APACHE Ⅲ scores decreased significantly in ulinastatin group(P<0.05).The mortality in ulinastatin group was also improved more significantly than that in control group(P<0.05).Conclusion Ulinastatin can decrease the concentrations of serum AOPP and CRP in patients with MODS,so as to alleviate the damage resulting from oxidative stress and inflammation,contributing to improve the outcome in patients with MODS.