The aim of this study was to elucidate the consequences of small bowel bacterial overgrowth (SBBO) after total gastrectomy. A total of 127 patients, evaluated for SBBO with a radiographically controlled H2-breath test (subgroup I, without SBBO, n = 80; subgroup II, with SBBO, n = 47) after potentially curative total gastrectomy for gastric malignancy, were uniformly evaluated. Mean time since operation was significantly shorter in subgroup II than in subgroup I [370 days, confidence interval (CI) 96-645 days, vs. 687 days, CI 397-976 days; P < 0.01]. Controlling for this difference, there were no other significant differences in symptoms and signs between the subgroups except for the medico-social functioning measured with the Edinburgh Rehabilitation Status Scale (ERSS). The mean ERSS showed significantly better medicosocial functioning in subgroup I than in subgroup II [3.7 (CI 2.2-5.2) vs. 5.1 (CI 3.0-7.0); P < 0.05]. After total gastrectomy, patients without SBBO did not differ significantly from patients with SBBO in most parameters. Medicosocial functioning was significantly poorer in the latter.