Rapid and effective rehydration should be the major function of ORS and sports drinks to promote optimal performance during exercise and also in cases where dehydration is induced by diarrhea. Based on an extensive review of the literature, water absorption from a CHO-E solution in the human small intestine is influenced by solution CHO concentration, CHO type, number of transportable CHOs (single vs multiple), osmolality, different segments of the small intestine, and exercise. These factors exert a significant effect on water absorption independently and/or interactively. Although some potential or proposed mechanisms for water and solute absorption are discussed, more studies in this area are needed for a better understanding of water and solute absorption associated with these influencing factors in different regions of the small intestine. The authors did not make any specific recommendations regarding composition of CHO-E solutions.