The purpose of the present invention is to provide a process for producing an aqueous solution containing a fat-soluble substance. A combination of a super dissolution aid, cyclodextrin and a fat-soluble substance or a combination of the super dis-solution aid and a cyclodextrin complex of the fat-soluble substance is used for dissolving the fat-soluble substance, whereby it becomes possible to provide an aqueous solution containing the fat-soluble substance at a high concentration and an aqueous solution having improved transdermal absorbability of the fat-soluble substance contained therein.
