Provided is a medicinal composition characterized by comprising an alkyl ether derivative represented by general formula [1] [wherein: R1 and R2 are the same or different and represent a hydrogen atom, a halogen atom, an optionally substituted C1-6 alkyl group, an optionally substituted aryl group, etc.; R3 represents an optionally protected hydroxyl group, etc.; and m and n are the same or different and represent an integer of 1 to 6] or a salt thereof. The medicinal composition according to the present invention is useful as a post nerve injury rehabilitation effect-enhancing agent.