The effects of retrograde luminal perfusion of a 75 cm jejunal segment on absorption, transit time and myoelectrical activity were studied in four dogs. Retrograde perfusion increased jejunal absorption of water (0.016-0.021 ml cm intestinal length-1 min-1. P less than 0.001) together with sodium (1.15-1.82 mumol cm-1 min-1; P less than 0.001) and glucose (1.98-2.27 mumol cm-1 min-1; P less than 0.01). Mean jejunal transit time was prolonged (9.2-13.9 min; P less than 0.001) and jejunal spike activity was reduced compared with antegrade perfusion (14.5-4% of slow wave frequency; P less than 0.01). These results suggest that the reversal of small bowel segments in the treatment of the short bowel syndrome can result in an increase in absorption from the reversed segment itself in addition to any effect from delayed transit in the proximal bowel.