The relationship between gastroduodenal motility and bile reflux was studied in normal rats and in rats subjected to hemorrhage and blood reinfusion. Bile secretion decreased from 5.3 +/- 0.4 to 4.1 +/- 0.5 microL/(min.100 g rat) (p less than 0.05) during the hypovolemic stress and recovered after blood reinfusion. Gastric bile salt content was low (0.1 +/- 0.03 mumol/(h.100 g rat] during control period and hemorrhage but increased to 0.7 +/- 0.12 mumol/(h.100 g rat) (p less than 0.001) during the 3 h following blood replacement. Marked gastric and duodenal retention of polyethylene glycol was observed immediately after hypovolemia with the former being evident even after 3 h following blood reinfusion, while duodenal emptying recovered rapidly after reinfusion. The frequency of gastric contraction remained unchanged during hemorrhage but decreased after 90 min following blood replacement, whereas the frequency of duodenal contraction abruptly decreased during hemorrhage and recovered after reinfusion. Both gastric and duodenal contractile pressure was significantly decreased during hemorrhage. After reinfusion, the former remained suppressed while the latter was fully recovered within 1 h. Thus, a significant duodenogastric bile reflux observed after reinfusion was due to a higher duodenal contractile pressure, and the uncoordinated gastroduodenal motility with the duodenal motility fully recovered soon after reinfusion while that of the stomach remained suppressed.