Abstract: An identification label changes color in an irreversible manner once put into contact with water/humidity. The label has a water-absorbable paper-based substrate having a surface on which an ink zone formed by printing of water-repellent or hydrophobic ink thereon and an opposite second surface on which a coating layer is formed. The ink zone has a color substantially identical to color of the substrate. The coating layer contains water soluble substance, which dissolves into water to form a solution that, once being absorbed by the substrate, changes the color of the substrate, the color of the solution being different from that of the substrate. A layer of adhesive is formed below the coating layer. Alternatively, the coating layer is formed on a surface of a double-sided adhesive layer and is bonded to a surface of the substrate opposite to the surface on which the ink zone is formed.