Endotoxin (Et) adsorption therapy with a column of polymyxin B-immobilized fibers (PMX) is effective in improving the partial pressure of arterial oxygen/fraction of inspired oxygen ratio (PaO(2)/FiO(2) ratio) and increasing mean arterial blood pressure (MAP) in sepsis. S100A12 and soluble receptor for advanced glycation end product (sRAGE) are useful as early markers of acute lung injury. To investigate the effect of improving the PaO(2)/FiO(2) ratio by PMX-direct hemoperfusion (PMX-DHP) on production of S100A12 and sRAGE. Sepsis patients after surgery for perforation of the lower gastrointestinal tract were adopted as the subjects. We retrospectively reviewed the cases of 20 patients on mechanical ventilation and continuous administration of norepinephrine. We recorded PaO(2)/FiO(2) ratio, MAP, and norepinephrine doses. S100A12, sRAGE, and Et levels were measured before and after PMX-DHP. The PaO(2)/FiO(2) ratio and MAP improved significantly after PMX-DHP (p < 0.05). S100A12 and Et decreased significantly after PMX-DHP (p < 0.05). No differences were observed in sRAGE. S100A12 is useful as a marker that reflected improvement in the PaO(2)/FiO(2) ratio after PMX-DHP. We consider PMX-DHP to be useful as adjunctive therapy for sepsis that reduces the Et and corrects the pathology in the early stage. Copyright © 2011 S. Karger AG, Basel.