Polysaccharide polymers are widely used in solution to provide structure and function, e.g., viscoelasticity, colloidal stability, and delivery of actives. Underlying these functions are inter- and intra-molecular interactions that depend greatly on the solvent used. This presentation will highlight our ongoing phase behavior, structural (light and small-angle X-ray scattering) and rheological investigation of solvent effects on polysaccharides, with a focus on dextran and cellulose derivatives dissolved in mixtures of a good solvent (water, formamide, ethanolamine) and a non-solvent (ethanol) as a minor component. The observed effects on the polymer conformation are discussed in terms of intermolecular interactions and are correlated with the solvent Hansen solubility parameters.