AIM: To investigate the effectiveness of direct hemo- perfusion with polymyxin B-immobilized fibers (DHP- PMX therapy) on warm ischemia-reperfusion (I/R) injury of the small intestine. METHODS: The proximal jejunum and distal ileum of mongrel dogs were resected. Warm ischemia was performed by clamping the superior mesenteric artery (SMA) and vein (SMV) for 2 h. Blood flow to the proximal small intestine was restored 1 h after reperfusion, and the distal small intestine was used as a stoma. The experiment was discontinued 6 h after reperfusion. The dogs were divided into two groups: the DHP-PMX group (n = 6, DHP-PMX was performed for 180 min; from 10 min prior to reperfusion to 170 min after reperfusion) and the control group (n = 5). The rate pressure product (RPP), SMA blood flow, mucosal tissue blood flow, and intramucosal pH (pHi) were compared between the two groups. The serum interleukin (IL)-10 levels measured 170 min after reperfusion were also compared. RESULTS: The RPP at 6 h after reperfusion was significantly higher in the PMX group than in the control group (12 174 ± 1832 mmHg/min vs 8929 ± 1797 mmHg/min, P < 0.05). The recovery rates ofthe SMA blood flow at 1 and 6 h after reperfusion were significantly better in the PMX group than in the control group (61% ± 7% vs 44% ± 4%, P < 0.05, and 59% ± 5% vs 35% ± 5%, P < 0.05, respectively). The recovery rate of the mucosal tissue blood flow and the pHi levels at 6 h after reperfusion were significantly higher in the PMX group (61% ± 8% vs 31% ± 3%, P < 0.05 and 7.91 ± 0.06 vs 7.69 ± 0.08, P < 0.05, respectively). In addition, the serum IL-10 levels just before DHP-PMX removal were significantly higher in the PMX group than in the control group (1 569 ± 253 pg/mL vs 211 ± 40 pg/mL, P < 0.05). CONCLUSION: DHP-PMX therapy reduced warm I/R injury of the small intestine. IL-10 may play a role in inhibiting I/R injury during DHP-PMX therapy. AIM: To investigate the effectiveness of direct hemo- perfusion with polymyxin B-immobilized fibers (DHP-PMX therapy) on warm ischemia-reperfusion (I / R) injury of the small intestine. METHODS: The proximal jejunum and distal ileum of mongrel dogs Warm ischemia was performed by clamping the superior mesenteric artery (SMA) and vein (SMV) for 2 h. Blood flow to the proximal small intestine was restored 1 h after reperfusion, and the distal small intestine was used as a stoma. The dogs were divided into two groups: the DHP-PMX group (n = 6, DHP-PMX was performed for 180 min; from 10 min prior to reperfusion to 170 min after reperfusion) and the The rate pressure product (RPP), SMA blood flow, mucosal tissue blood flow, and intramucosal pH (pHi) were compared between the two groups. The serum pressure (RPG) -10 levels measured 170 min after reperfusion were also compared. RESULTS: The RPP at 6 h After reperfusion was significantly higher in the PMX group than in the control group (12 174 ± 1832 mmHg / min vs 8929 ± 1797 mmHg / min, P <0.05). The recovery rates of the SMA blood flow at 1 and 6 h after reperfusion were significantly better in the PMX group than in the control group (61% ± 7% vs 44% ± 4%, P <0.05, and 59% ± 5% vs 35% ± 5%, respectively). rate of the mucosal tissue blood flow and the pHi levels at 6 h after reperfusion were significantly higher in the PMX group (61% ± 8% vs 31% ± 3%, P <0.05 and 7.91 ± 0.06 vs 7.69 ± 0.08, P < 0.05, respectively). In addition, the serum IL-10 levels were just before DHP-PMX removal were higher in the PMX group than in the control group (1 569 ± 253 pg / mL vs 211 ± 40 pg / mL, P < 0.05). CONCLUSION: DHP-PMX therapy reduced warm I / R injury of the small intestine. IL-10 may play a role in inhibiting I / R injury during DHP-PMX therapy.