Provided are: an aqueous solution capable of being administered to a living body, wherein said aqueous solution has a function to sufficiently supply oxygen to a peripheral cell, causes little damages or injuries of a cell under a low-oxygen or anaerobic stimulation, has a sufficiently high effect to protect a cell, and can exhibit these effects steadily and sustainably and a method for producing the aqueous solution. The aqueous solution capable of being administered to a living body according to the present invention contains oxygen nano-bubbles, wherein the average particle diameter and the density of the oxygen nano-bubbles are respectively 30 nm or less and 1016 particles or more per 1 ml, preferably 1 to 10 nm and 1017 particles or more per 1 ml, as measured by an ice embedding method using a cryogenic transmission electron microscope. The aqueous solution capable of being administered to a living body according to the present invention contains oxygen nano-bubbles which are produced by ejecting an aqueous solution containing dissolved oxygen from the outside of a cylinder having two or more small through-holes in a circumferential direction through the small through-holes at a pressure equal to or higher than the atmospheric pressure, so that the aqueous solution can get hit in such a manner that water hammering is focused at the center of the cylinder on the same plane that is parallel with a radius-direction cross section of the cylinder.Linvention concerne : une solution aqueuse pouvant être administrée à un corps vivant, ladite solution aqueuse présentant une fonction pour fournir suffisamment doxygène à une cellule périphérique, provoquant peu de dommages ou de lésions à une cellule sous une stimulation à faible teneur en oxygène ou anaérobie, présentant un effet suffisamment élevé pour protéger une cellule et pouvant présenter ces effets de manière stable et durable et un procédé de production de la solution aqueuse. La solution aqueuse pouvant être ad
