Abstract: The polyvinyl alcohol (PVA)-based gel of the invention is reversibly hydrated so that the gel after complete drying can again absorb water to regain the highly elastic gel-like form. Such a reversibly hydrated PVA-base gel can be prepared by impregnating a hydrated gel of PVA with an ethylenically unsaturated, water-soluble ionic monomer together with or without a free-radical polymerization initiator and bringing the thus monomer-impregnated PVA gel under conditions to cause in situ polymerization of the monomer, e.g., by heating or irradiating with actinic rays such as ultraviolet light.