Problem to Be Solved by the Invention:To providing a method for ameliorating DHIC.Means for Solving the Problem:This invention is directed to a treating method for DHIC, comprising the step of administering a therapeutically effective amount of 3-(15-hydroxypentadecyl)-2,4,4-trimethyl-2-cyclohexene-1-one, a salt thereof, or a solvate thereof.