Flow behavior of nanosize alumina suspensions in the presence of polyalcohols was investigated. Viscosity of high solids content (35 vol%) alumina nanopowders was measured at room temperature. It was shown that after the first advancing shear rate branch, viscosity measurements show excellent reproducibility. All the suspensions showed the formation of large clusters, which are broken down as shear rate increases indicating reversible cluster breaking and reforming. Viscosity of suspensions decreases dramatically with up to 10 wt% polyalcohol addition. Only ethylene glycol showed an increase in viscosity indicating no interaction with the particle surface. The addition of polyalcohols is believed to prevent the formation of large and/or strong clusters by modifying the alumina particle surface. The exact nature and quantitative description of viscosity reduction by polyalcohol addition have yet to be established.