Hydrogen-enriched saline prevents liver ischemia/reperfusion-induced HMGB1 over-expression and release. Male Sprague Dawley rats were subject to partial warm liver ischemia/reperfusion injury with either intraperitoneal injection of normal saline or hydrogen enriched saline at a dose of 10 ml/kg, 10 minutes before reperfusion. HMGB1 over expression in the liver were assessed by immunostaining and western blot. Serum levels were assayed by western blot. Examples of microphotographs stained for HMGB1 (seen as a brown precipitation both within the cytoplasm and nucleus, original magnification × 400): (A) sham-control, (B) 2 hours after reperfusion with normal saline, or (C) 2 after reperfusion with hydrogen enriched saline. (D) Western blot analysis for HMGB1 was performed on both liver sections and (E) serum samples collected from rats 2, 6, 12 and 24 hours after reperfusion. Sham-operated animals underwent laparotomy only. Mean ± SEM (n = 6); *p < 0.05.