The inclusion complex-forming ability of three glucosyl-cyclodextrins (CDs), 6-Ο-α-D-glucosyl-α-CD (G-α-CD), 6-Ο-α-D-glucosyl-β-CD (G-β-CD), and 6^A, 6^D-di-Ο-α-D-glucosyl-β-CD (2G-β-CD) with slightly soluble or insoluble drugs in aqueous solution and in the solid state was studied by the solubility method, ultraviolet spectroscopy, and differential scanning calorimetry. These glucosyl-CDs were capable of forming inclusion complexes with compounds which can form complexes with the parent CDs. The enhancement of solubility of poorly water-soluble drugs by glucosyl-β-CDs was much more marked than that by β-CD. The hemolytic activity of glucosyl-CD was lower than that of each parent CD. The estriol-glucosyl-β-CD complex may be practically applicable to injectable preparations because of its high water-solubility and low hemolytic activity.