In 34 patients with penetrating colon wounds which were considered to be liable to dehiscence, the sutured wounds were exteriorized. There were several 'high-risk' factors, i.e. operative delay of more than 6 hours after injury, faecal contamination of the peritoneal cavity, marked contusion of the bowel wall, and severe associated visceral haematoma which is deemed liable to infection. Additional considerations were thoraco-abdominal penetration and combined colonic and renal injuries. The operative technique is described in detail, and the morbidity of the procedure, which is low, is analysed. Comparison is made with a similar group of patients in whom colostomy was performed with subsequent closure. Exteriorization and closure of the penetrating colon wound appear significantly superior to colostomy in terms of mortality, septic complications and period of hospitalization.