In order to evaluate the effects that an increase in duodenogastric reflux (DGR) has on the mucosal cell proliferation of the non-operated stomach, we made a prospective study on 13 patients (9 female and 4 male, mean age 52 years) both before and 6 months after cholecystectomy, an operation which determines a significant increase in DGR with an intact pyloric sphincter. DGR was evaluated by measuring total intragastric bile acids (dosed by an enzymatic method), and single intragastric bile acids (dosed by High Performance Liquid Chromatography) and it was expressed as Fasting Bile Reflux (FBR) in mumol/h. Gastric cell proliferation was evaluated by measuring (by High Performance Liquid Chromatography) polyamine (putrescine, spermidine and spermine) levels in biopsy specimens taken from the antrum and gastric body. The histology of the antrum and gastric body was also evaluated. After cholecystectomy, there was a significant increase in DGR (delta = 39.23 mumol/h, 95% C.L. 11.69-136.22, sign-test for matched pairs p = 0.0003). The tissue concentration of putrescine in the antrum increased significantly (delta = 8.36 mumol/g of tissue, 95% C.L. 0.34-18.01, sign-test for matched pairs p = 0.013) and there was a worsening of histological findings in the antrum (preoperative chronic atrophic gastritis rate 38.5%, postoperative 69%). In the body there were no significant variations either in polyamine levels or in histology. The increase in DGR and in putrescine concentrations in the antrum were associated negatively (Spearman's rank -0.64, 95% C.L. -0.88 to -0.14).(ABSTRACT TRUNCATED AT 250 WORDS)