The aim of this study was to examine the effect of decontamination as compared to placebo medication on post-gastrectomy treatment costs. The results of a prospective double-blind placebo-controlled multicenter trial indicate that perioperative i.v. prophylaxis with cefotaxim and topical decontamination with polymyxin B, tobramycin, vancomycin and amphotericin B from the day before surgery until the 7th postoperative day is most effective in the prevention of esophagojejunal anastomotic leakage following total gastrectomy. For the cost analysis, only patients who had been decontaminated according to the study protocol (n = 90) were compared to the non-decontaminated patients (n = 103). The esophagojejunal leakage rate was 10.6% in placebo patients (n = 103) and could be reduced significantly to 1.1% in decontaminated patients (n = 90, P = 0.0061; two-tailed Fisher's exact test). There was only one asymptomatic leakage detected on Gastrografin swallow. The pulmonary infection (P = 0.0173) and overall complication rates (p = 0.0238) were significantly reduced in the decontamination group as well. During the observation period, 9 (8.7%) patients in the placebo group and 3 (3.3%) in the decontaminated group died (P = n.s.). Patients were followed up for the initial 42 postoperative days and treatment costs were calculated for this time period only. The parameters compiled in the study pertaining to use of medical resources formed the basis for the determination of the postoperative treatment costs. These were the costs for decontaminating drugs, intravenous antibiotics, reoperations and non-surgical reinterventions as well as daily treatment costs of the general ward, the intensive care unit (ICU) and rehabilitation. The average costs per patient in the placebo group amounted to DM 20,000 while the costs for decontaminated patients were only DM 16,200, which was due to a significantly lower number of patients requiring treatment in the ICU (P = 0.0082), significantly fewer patients requiring i.v. antibiotics (P = 0.0232) and fewer patients with reoperations (P = 0.0909). The prophylaxis employing decontaminating drugs in the amount of DM 400 lowered post-gastrectomy treatment costs by DM 3800 or 19%. The prophylaxis can be recommended, because it lowers morbidity, mortality and the costs of total gastrectomy.