Intestinal fatty acid binding protein (I-FABP) is an intracellular epithelial protein in the intestinal mucosa of many animals. IFABP appears in the circulation following epithelial damage, and in humans, is proven to be a parameter for damage to the mucosa. In this paper, an ELISA test designed for human I-FABP analysis was used to assay pig blood samples. The test recognized I-FABP cloned from pig small intestine and expressed in Escherichia coli. Furthermore, in our experimental model of (low flow) intestinal ischemia and reperfusion a significant rise in plasma I-FABP concentrations 15-30 min after clamping of the mesenteric artery was demonstrated. This is the first report that in pigs circulating I-FABP is a useful marker for (mild) intestinal injury, and could possibly be used to monitor (intestinal) health in clinical practice. (C) 2004 Elsevier Ltd. All rights reserved.