Maltosyl(G2)-erythritol, produced by the transglycosylation reaction of erythritol with maltotriose by Bacillus stearothermophilus maltogenic amylase, was not utilized either as a substrate for lactic acid production or for water-insoluble glucan synthesis. An inhibition assay of dextransucrase and mutansucrase showed that the dental caries suppression effect of G2-erythritol was greater than that of erythritol.