The chemical composition of coconut water shows a great variability during its maturational process and in no instance this fluid can be considered as an oral rehydration under scientific basis. The jejunal transport of water, sodium and glucose was studied in rats in vivo with coconut water during the different stages of maturation of the fruit. There was water absorption (mean = 1.07 ± 0.45 ml/min/cm), sodium secretion (mean = -169.04 ± 29.06 mEq/min/cm) and glucose absorption (mean = 5212.70 ± 2098.47 mg%/min/cm) in all the stages studied. This study demonstrates that sodium secretion impedes considering coconut water a rehidrating solution.