p38 mitogen-activated protein kinase (MAPK) has been reported to regulate the inflammatory response in various cell types via extracellular stimuli. p38 MAPK activation also results in the induction of heme oxygenase (HO)-1 which exerts potent anti-inflammatory effects. Although studies have shown that 17-estradiol (E2) prevented organ dysfunction following trauma-hemorrhage, it remains unknown whether p38 MAPK/HO-1 plays any role in E2-mediated attenuation of intestinal injury under those conditions. To study this, male rats underwent trauma-hemorrhage (mean BP ~40 mmHg for 90 min) followed by fluid resuscitation. At the onset of resuscitation, rats were treated with vehicle, E2 (1 mg/kg BW), the p38 MAPK inhibitor SB203580 (2 mg/kg BW) or E2 plus SB203580. Two h thereafter, intestinal myeloperoxidase (MPO) activity and lactate, tumor necrosis factor (TNF)-, interleukin (IL)-6, intercellular adhesion molecule (ICAM)-1, cytokine-induced neutrophil chemoattractant (CINC)-1, and macrophage inflammatory protein (MIP)-2 levels were measured. Intestinal p38 MAPK and HO-1 protein levels were also determined. Trauma-hemorrhage led to an increase in intestinal MPO activity and lactate, TNF-, IL-6, ICAM-1, CINC-1, and MIP-2 levels. This was accompanied with a decrease in intestinal p38 MAPK activity and increase in HO-1 expression. Administration of E2 normalized all the above parameters except HO-1 which was further increased following trauma-hemorrhage. Administration of SB203580 with E2 abolished the E2-mediated restoration of the above parameters as well as the increase in intestinal HO-1 expression following trauma-hemorrhage. These results suggest that the p38 MAPK/HO-1 pathway plays a critical role in mediating the salutary effects of E2 on shock-induced intestinal injury.