The present invention, amongst others, relates to a pharmaceutical composition comprising (a) a thiazole derivative represented by the formula (I)wherein R1 represents aryl, aralkyl, an aromatic heterocyclic group, aromatic heterocycle-alkyl, aliphatic heterocycle-alkyl or tetrahydropyranyloxy, each of which is optionally substituted by 1 to 3 substituents selected from the group consisting of halogen； lower alkyl optionally substituted by lower alkoxy or morpholino； lower alkoxy； lower alkanoyl； and vinyl, and R2 represents pyridyl or tetrahydropyranyl, or a pharmaceutically acceptable salt thereof, and (b) L-DOPA and/or a dopamine agonist.
