Diagnostic peritoneal lavage was 97 percent accurate, with a 2 percent false positive rate and a 1 percent false negative rate in this series of 414 patients. The ease, safety, and accuracy of diagnostic peritoneal lavage justify its continued use in evaluating these patients. Recent studies show computerized tomography (CT) can be highly accurate in detecting intra-abdominal injuries after blunt trauma. We reviewed our experience with diagnostic peritoneal lavage (DPL) to evaluate whether the accuracy, safety, speed, and cost justified its continued use. Four hundred fifteen DPLs were performed on 414 patients from February 1, 1983, through December 31, 1987. All DPLs were done by the open technique. The lavage was considered grossly positive if 10 cc gross blood were aspirated. If there were greater than 100,000 red blood cells (RBC)/mm3, greater than 500 white blood cells (WBC)/mm3, elevated amylase or bilirubin, or bacteria or vegetable fibers the lavage was microscopically positive. There were no cases with elevated bilirubin, amylase, or presence of bacteria. All four cases with "rare vegetable fibers" were false positive. Six DPLs were for penetrating trauma to the lower chest or back. There were 291 negative lavages, including five false negatives (1%), and 124 positive DPLs, including seven false positives (2%), resulting in a crude accuracy of 97 percent. Three of the five false negative lavages had a ruptured diaphragm as the only intra-abdominal injury. There was one minor complication. DPL was usually performed in the trauma resuscitation room during the secondary survey. At our institution, the total fees for DPL are +185 less than the fees for CT. DPL is accurate, rapid, safe, and avoids the disruption of patient care that results in the radiology suite. DPL remains our procedure of choice for evaluating blunt abdominal trauma in the adult.