The invention relates to a crystalline hydrate of 1-chloro-4-(.beta.-D-glucopyranos-1-yl)-2-(4-ethynyl-benzyl)-benzene and to crystalline complexes between 1-chloro-4-(.beta.-D-glucopyranos-1-yl)-2-(4-ethynyl-benzyl)-benzene and a natural amino acid, to methods for the preparation thereof, as well as to uses thereof for preparing medicaments.