A therapeutic or prophylactic agent for multiple sclerosis is disclosed. Thetherapeutic or prophylactic agent comprises as an effective ingredient aglycinederivative having a specific structure or a pharmaceutically acceptable saltthereof,for example, the below-described compound[(E)-2-(2,6-dichlorobenzamido)-5-[4-(isopropyl-pyrimidin-2-ylamino)phenyl]pent-4-enoic acid].The therapeutic orprophylactic agent for multiple sclerosis according to the present inventionshows theexcellent absorbability and in vivo stability when orally administered, andexhibitshigh therapeutic or prophylactic effects.(see above formula)
