Inflammatory bowel disease is a group of chronic inflammatory disorders of unknown etiolo- gy involving the gastrointestinal tract. Wakefield et al suggested that Crohns disease is medi- ated by multifocal gastrointestinal infarction and recently Gaffney reported that marked im- provement in the patients with ulcerative colitis were noticed during treatment with heparin. This study was performed to find out, whether intrarectal infusion of TNBS 50mg into t.he rab- bit causes acute colitis or not, and whether warfarin pretreatment. Prevent.s colonic damage in duced by TNBS or not. The rabbits were randomly assigned to one of two groups, warfar in pretreated(N=6) and non treated(N=6). Warfarin solution was infused through the ear vein of the rabbit and TNBS 50mg was instilled into the colon of the rabbit. The rabbits were sacri ficed and the degree of colonic damage was recorded as visual analogue scale and microscopic findings. The results showed that intrarectal infusion of TNBS 50mg caused acut.e necrotic co litis, but warfarin pretreatment did not prevent TNBS induced acute colitis.(Korean J Gastro- enterol 1994; 26: 458 464)