Etappenlavage is defined as a series of planned multiple operative procedures performed at a 24-hour interval. It includes a commitment to reexplore the patient's abdomen at the initial corrective operation. This is a report of a prospective study of 117 patients treated by etappenlavage for severe advanced suppurative peritonitis in 2 institutions. Etappenlavage was performed in 15% of all patients with operations for peritonitis. In these patients, the abdominal infection had progressed to an advanced stage of severe functional impairment. A total of 669 laparotomies were performed and the abdomen closed temporarily utilizing retention sutures (n = 45), a simple zipper (n = 26), a slide fastener (n = 29), and Velcro analogue (n = 17). An average of 6.1 procedures were necessary to control the infection. In 57% of the patients, additional complications were recognized and repaired after the initial operation. Patients were artificially ventilated for an average of 17 days. The median duration of therapy was 33 (range, 3-183) days. Twenty-eight patients died between days 3 and 71 (median, 9) after initiation of therapy. In 88%, uncomplicated wound healing was observed after wounds were closed definitely. In the last 17 patients, no complications were attributable to the use of 2 adhesive sheets of polyamide plus nylon or perlon for temporary abdomimal closure (Velcro-like artificial burr). APACHE II scoring predicted a median mortality of 47%. The actual mortality was 25%. Overall, the mortality of advanced diffuse peritonitis was reduced from a predicted 34-93% (APACHE II/SIS scoring) to 24%. Velcro analogue (artificial burr) was the most practical device for temporary abdominal closure.