A method for treating side effects of anticancer agent includes administering to a subject in need thereof a prophylactic and/or therapeutic agent containing a therapeutically effective amount of a compound shown by the following Formula (I):R1—NHCH2COCH2CH2COOR2 (I)wherein R1 represents a hydrogen atom or an acyl group, and R2 represents a hydrogen atom, a linear or branched alkyl group, a cycloalkyl group, an aryl group, or an aralkyl group, or a salt thereof.
