Results of photon correlation spectroscopy and viscosity measurements performed in trehalose aqueous solutions are reported. The light scattering experimental findings reveal a peculiar behavior of the effective diffusion coefficient D-eff which, in the diluite region and in a limited temperature range, shows strong changes. This behavior suggests a great sensitivity of the system structure to temperature changes. On the other hand, the temperature dependence of shear viscosity eta confirms the noticeable kinetically fragile character of these systems.