Preventing negative laparotomies is one of the most challenging problems in the management of penetrating abdominal injuries. The term "selective laparotomy" has been therefore introduced and has found an ever increasing acceptance. The peritoneal lavage is a useful tool in patient selection for laparotomy but the main problem is where to set the boundary between a positive and a negative peritoneal lavage. The manipulation of this boundary leads to significant changes in the sensitivity and specificity of the peritoneal lavage. Here we are presenting 162 consecutive cases of penetrating abdominal trauma and discussing our methods of evaluation and management.