Efficacy of a standard United Kingdom oral rehydration solution (ORS) and a hypotonic ORS assessed by human intestinal perfusion.

Human triple-lumen intestinal perfusion was used to compare water and solute absorption from the oral rehydration solution (ORS) most widely used in the United Kingdom and a new experimental hypotonic ORS (HYPO-ORS). HYPO-ORS (osmolality 210 mOsm/kg) promoted significantly greater water absorption than UK-ORS (7.03 +/- 1.1 vs 2.73 +/- 1.0 ml cm-1 h-1; P less than 0.01). HYPO-ORS produced net sodium and chloride absorption whereas the low sodium UK-ORS produced a net secretion of these ions. Bicarbonate absorption was also greater from HYPO-ORS although potassium and glucose absorption were similar from both solutions. This study suggests that UK-ORS may not promote optimal water and solute absorption and that clinical studies with HYPO-ORS are indicated.