A method for ameliorating and/or preventing chronic kidney disease includes administering to a subject in need thereof an agent containing 5-aminolevulinic acid (ALA) or a derivative thereof, or a salt thereof as an active ingredient. Preferably, these ALAs contain a metal-containing compound, such as sodium ferrous citrate. The above-mentioned ALAs, ALA； various esters, such as ALA methylester, ALA ethylester, ALA propylester, ALA butylester, and ALA pentylester； and hydrochlorides, phosphates, and sulfates, and the like of these ALA esters are preferred examples.
