BLUNT abdominal trauma incurs a mortality as high as 45.6%1 in some areas largely due to undiagnosed abdominal visceral injury in association with head and chest injuries. To reduce this high mortality, a more dependable means of detecting intraperitoneal visceral injury, diagnostic peritoneal lavage, was developed in 1964.2 This simple technique will disclose even small amounts of blood within the peritoneal cavity regardless of the source and has been utilized now in nearly 190 patients. However, in an instance of a child with a ruptured distal ileum, no blood was found in peritoneal lavage, but many polymorphonuclear leukocytes were noted in the returning opalescent perfusate. This observation prompted the current laboratory study of the pathophysiology of the traumatized peritoneum. We were particularly interested in determining the dynamics of white blood cell (WBC) appearance in the peritoneal cavity to see if such data might be employed clinically.