Postoperative ileus (POI) affects patients after abdominal surgery. (1,4) Standardized rodent models of intestinal manipulation represent the surgical trauma. POI is induced by local inflammation in the intestinal muscularis. (7) This inflammation is due to an activation of resident muscularis macrophages leading to paralysis of intestinal myocytes. (5,11) This disseminates along the entire gastrointestinal tract, the so called gastrointestinal field effect. (8) Former authors provided the description of this phenomenon, but the underlying pathomechanism remained unclear. (8,9) There were hints for an immunological interaction. (6,10) In the December issue of Nature Medicine 2010 we demonstrated that memory T helper type 1 cells are responsible for the gastrointestinal field effect. We established a modified protocol to isolate dendritic cells and T cells separately from the intestinal muscularis and the mucosa/submucosa layer for further phenotypical, functional and in vitro studies offering the advantage to study cells of two functionally different layers (muscularis vs. mucosa/submucosa) of the bowel wall simultaneously in contrast to established isolation protocols. (2,3) Isolation of smaller cell amounts of the tunica muscularis is possible. Isolated cells could be used for phenotypical and functional analysis by FACS, ELISA, transmigration assays and (co-)culture systems. Cell pooling is not needed in our protocol.