The invention relates to liquid vehicles that can be used to create dilute solutions of water-soluble pharmaceutical or non-pharmaceutical oral contrast agents. The liquid vehicles are formulated to provide desired osmolalities, viscosities, pH, and taste masking capabilities to match the particular intentions of the user and to complement the inherent differences in the various oral contrast agents. The liquid vehicles comprise an aqueous medium, an osmotic agent to adjust osmolality, a buffering agent, a viscosity agent, and sweeteners and flavoring agents to improve palatability.