The pathogenesis of Alzheimer's disease is known to be related to the glycosaminoglycans that are associated with the deposition of amyloid beta (A beta) peptides. We prepared heparin-mimicking multimeric saccharides and investigated their interactions with A beta peptides in solution. The results showed that multimeric saccharides, especially the dimeric saccharide, strongly inhibited 3-sheeted A beta aggregation as assessed by the thioflavin-T (Th-T) assay, average zeta potential measurements and atomic force microscopy (AFM). This result suggested that the amyloidosis of A beta (1-42) was affected by the multivalency of saccharides even in the solution.