The present paper reports on the study of the disaccharides' dynamics in aqueous solutions and discusses the role of their interaction with water, which seems to be responsible for the protective action on biological membranes and tissues. In particular, using QENS (IRIS at ISIS, RAL, U.K.) we compared the quasielastic spectra from three homologous disaccharides (trehalose, maltose, and sucrose) with a hydration of 20 water molecules per each disaccharide molecule. The isotopic substitution method allowed us to study also the dynamics of water in the presence of the disaccharides. Our results show that trehalose is the most effective in slowing down the water dynamics, inducing a more extensive hydration layer.