The cell kinetics of gastric epithelium were studied by bromodeoxyuridine (BrdU) and flow cytometry in seven patients with remnant stomachs reconstructed with a Billroth type II procedure and in 25 patients with whole stomachs. Each patient received an intravenous injection of BrdU (200 mg/m2) 6 hours before surgery. Fresh specimens obtained from the lesser curvature, greater curvature, and stomal areas in the cases of remnant stomachs and from the antrum and fundus in the case of whole stomachs were studied. The BrdU labeling index was higher in the stomal area of the gastric remnant than in other areas, and DNA synthesis time was shortened in the stomal area of the gastric remnant (P less than 0.01) but not in other areas. The turnover time of the mucosa in the stomal area was 4.1 +/- 1.2 days, significantly shorter (P less than 0.01) than in other areas (7.6 +/- 2.3 to 8.2 +/- 1.2 days). The present study showed that the cell proliferation was extremely rapid in the stomal area of the gastric remnant, suggesting that this enhanced turnover of epithelial cells may assist in promoting carcinogenesis in the stomal area of the gastric remnant.