From 1980 to 1984, 500 asymptomatic patients with anterior abdominal stab wounds found to have penetrated the anterior peritoneal cavity on local wound exploration in the emergency center were evaluated by the technique of open peritoneal tap, quantitative diagnostic peritoneal lavage, or both. The technique was found to have several advantages, including earlier diagnosis of intraperitoneal visceral injuries in asymptomatic patients and a significant lowering of the incidence of unnecessary celiotomies in a busy county hospital. Also, it was extremely cost-effective. The major disadvantages were the number of false-positive results of taps and lavages based on red blood cell counts of more than 100,000/mm3, all of which resulted from bleeding from abdominal wall stab wound sites. An accuracy rate of approximately 91 percent was maintained throughout the period of the study, whereas there were only 1.8 false-negative results of lavage per year. Local wound exploration coupled with open peritoneal tap and diagnostic peritoneal lavage is recommended as a rapid, safe, and cost-effective technique for the evaluation of large numbers of asymptomatic patients who present with anterior abdominal stab wounds.