Five female mini-pigs underwent total colectomy including resection of the ileocecal valve. Sparing the terminal rectum, we reformed an end-to-end anastomosis between terminal ileum and remaining rectal cuff. In a second series 8 female mini-pigs have been colectomized using the same model. To delay intestinal passage, in addition a 10-12 cm long reversed segment of terminal ileum has been inserted between small bowel and rectal stump. Both groups were compared with a group of normal unoperated mini-pigs in a study up to 1 year, observing intestinal transit time, blood chemistry and general development of the animals. It could be proved that the reversal of a small bowel segment in colectomized animals leads to a prolongation of the intestinal transit time, to normalization of electrolytes and general appearance. Colectomy was only survived by animals with a reversed segment. The clinical application of a reversed small bowel segment following total colectomy in 1 patient was successful.