The present invention provides a percutaneous absorption formulation including a patch having an adhesive layer disposed on a substrate and the adhesive layer contains ketotifen fumarate and tris(hydroxymethyl) aminomethane, and the patch is packaged in a hygroscopic packaging material. In the percutaneous absorption formulation, tris(hydroxymethyl)aminomethane particularly selected from various basic substances is incorporated, and by packaging the patch in a hygroscopic packaging material, the percutaneous absorptivity and content stability of a drug can be simultaneously improved and the yellowing of the drug can be suppressed. These effects can be further improved by the incorporation of propyl gallate, the use of an adhesive layer including an SIS-based adhesive base and a rosin ester-based adhesion imparting resin, and/or the removal of oxygen from the atmosphere in the inside of the packaging material.
