PROBLEM TO BE SOLVED: To provide a percutaneous absorption promoter that makes it possible to easily produce a percutaneous preparation having excellent percutaneous absorbency, using various active ingredients.SOLUTION: The present invention provides a percutaneous absorption promoting aid or a percutaneous absorption promoter containing an equimolar salt of a) a basic functional group-containing compound with a molecular weight of 50-120 and a melting point of at 50-350°C and b) an acidic functional group-containing compound with LogP of-4-7.3, which make it possible to produce a percutaneous preparation having excellent percutaneous absorbency, using various active ingredients.SELECTED DRAWING: Figure 1【課題】様々な活性成分を用いて、経皮吸収性の優れた経皮製剤を、容易に製造できる経皮吸収促進剤を提供すること。【解決手段】ａ）分子量が５０～１２０、融点が５０～３５０℃である塩基性官能基含有化合物と、ｂ）ＬｏｇＰが－４～７．３である酸性官能基含有化合物との等モル塩を含む経皮吸収促進助剤又は経皮吸収促進剤により、様々な活性成分を用いて経皮吸収性の優れた経皮製剤を提供する。【選択図】図１
