A therapeutic or prophylactic agent for multiple sclerosis is disclosed. The therapeutic or prophylactic agent comprises as an effective ingredient a glycine derivative having a specific structure or a pharmaceutically acceptable salt thereof, for example, the below-described compound [(E)-2-(2,6-dichlorobenzamido)-5-[4-(isopropyl-pyrimidin-2-ylamino)phenyl]pent-4-enoic acid]. The therapeutic or prophylactic agent for multiple sclerosis according to the present invention shows the excellent absorbability and in vivo stability when orally administered, and exhibits high therapeutic or prophylactic effects.
