To evaluate whether the small bowel can be distracted by mechanical stress in analogy to limb lengthening by osteodistraction, a gut-lengthening apparatus was designed. This distractor was placed at the antimesenterical side of a defined jejunum segment in rabbits. Distraction was performed by 1 mm lengthening of the distractor once daily using extracorporal screws. An effective gut lengthening was achieved of 9.9 +/- 0.5 mm (approximately 100%) within 3 weeks. Treated animals gained weight and remained in good general condition. Fasting plasma levels of cholecystokinin, neurotensin, glucagon-like peptide-1, gastric inhibitory polypeptide, and insulin remained unaffected. Postoperative factor XIII levels were significantly diminished and gastrin was elevated during gut distraction. DNA and protein concentrations in the mucosa of the distracted gut segments corresponded to controls. Mucosal lactase and saccharase activities were reduced. In the distracted bowel segments total tunica muscularis thickness was more than doubled due to muscle cell hypertrophy. In distracted segments villous width was increased. Detection of proliferating mucosal crypt cells utilizing BrdUrd labeling revealed no effects. In conclusion, small gut lengthening by mechanical distraction is possible without major changes in gut morphology. This technique may hint a novel experimental approach for the treatment of short bowel syndrome.