This study described the absorption of Na, K, Cl, H2O and sugars from an isosmotic sucrose electrolyte solution and compares it with the absorption of these substances from an isosmotic glucose electrolyte solution and a mannitol electrolyte solution, by an in vivo perfusion technique in the rat jejunum and ileum. The composition of the solutions was similar to the oral rehydrating solutions, currently in use for the treatment of acute diarrhoeal diseases. The study shows that an isosmotic sucrose containing electrolyte solution induces a significantly greater Na, Cl, and K absorption compared to glucose electrolyte solution. Water absorption however, is significantly less from the former solution probably due to osmotic drag of water into the lumen by the slowly absorbed fructose released from sucrose hydrolysis. These findings underline the clinical importance of using hyposmotic sucrose electrolyte solution for oral rehydration.