Bacterial infections constitute a major cause of morbidity and mortality after major liver resection and mechanisms of this type of complication have been poorly understood. The present study evaluated the translocation of enteric bacteria to mesenteric lymph nodes, viscera, and the systemic circulation and gut capillary permeability of a fine ultrastructural tracer in rats subjected to sham hepatectomy or 70% hepatectomy. Furthermore, the preventive effects of water-soluble ethylhydroxyethyl cellulose (EHEC) were studied. Cultures of all samples from rats subjected to sham hepatectomy or 70% hepatectomy with preoperative intravenous administration of EHEC were bacteriologically negative. The incidence of bacterial translocation from the gut to the systemic circulation and mesenteric lymph nodes was 30 and 80%, respectively (P < 0.01), and to the liver and kidneys 50 and 40%, respectively (P < 0.05), 12 hr after 70% hepatectomy. Intestinal capillary permeability and endothelial cell membrane permeability increased with the development of bacterial translocation. Translocating bacteria appeared within the cytoplasm of capillary endothelial cells. EHEC restored the changes in gut capillary permeability induced by major liver resection. These results indicate that gut capillary permeability may play an important role in maintaining the integrity of the gut barrier function and that increased permeability may be associated with the development of gut barrier failure.