1 The aim of our study was to investigate the eects of recombinant human granulocyte-colony stimulating factor in a rat model of splanchnic ischaemia-reperfusion injury. 2 Male anaesthetized rats were subjected to clamping of the splanchnic arteries for 45 min. This surgical procedure resulted in an irreversible state of shock (splanchnic artery occlusion shock; SAO shock). Sham operated animals were used as controls. Survival rate, serum tumour necrosis factor-a (TNF-a), neutrophil count, bone marrow myeloid precursor cells, myeloperoxidase activity (MPO; studied as a quantitative means to assess leukocyte accumulation), mean arterial blood pressure and the responsiveness of aortic rings to phenylephrine (PE, 1 nM ± 10 mM) were studied. 3 SAO shocked rats had a decreased survival rate (0% at 4 h of reperfusion, while sham shocked rats survived more than 4 h), increased serum levels of TNF-a (201+10 u ml 71