To describe the state of microcirculation in the intestinal wall in ulcerative colitis and Crohn's disease in own material.For morphological examination, we obtained tissue samples from both diseases during bioptic bowel examination from 11 patients. We fixed the samples with 10% buffered formalin, de-hydrated and covered with paraffin. From paraffin blocks, we made histological sections about 5μm thick with a microtome. They were always stained with haematoxylin and eosin. For immunohistochemistry sections, we either did or did not revitalise the sections according to the manufacturer's recommendations for specific to-reagents. For immunohistochemic examinations, we revitalised the sections by acquiring the heat-induced epitope in DakoCytomation Target Retrieval Solution, Code No S 1700, or in mmol.l-1 citrate buffer, pH 6.0. We did not dry the sections during such procedure. We used antibodies as follows: Monoclonal mouse antibodies against human von Willebrand factor, Clone F8/86 (DakoCytomation, Denmark), Monoclonal mouse antibodies against smooth muscle actine, Clone HHF35 (DakoCytomation, Denmark). We used detection system Dako EnVisionTM + Dual Link System-HPR (Dako, Denmark) or Dako Liquid DAB + Substrate Chromogen System (Dako, Denmark) to display areas of specific connection of antibodies. Antibodies against von Willebrand factor react in our samples with the endothelium of vessels and with precursors in the lining of peaks of villi. We have also seen a diffuse positive reaction. Lymphatic vessels do not display monoclonal antibodies (Fig. 4, Ref. 8).