PROBLEM TO BE SOLVED: To provide a novel water soluble embolic composition that is useful for treating liver cancer, etc., and can increase the viscosity of a water-soluble contrast medium.SOLUTION: Provided is an aqueous liquid embolic composition in which the viscosity of a water-soluble contrast medium is increased, obtained by mixing a water soluble contrast medium, such as iodixanol and ioxilan, that does not affect the diagnosis of liver cancer, in particular also the post-operative follow-up CT examination, and a viscosity improver such as polyethylene glycol, polyvinyl pyrrolidone and dextran.SELECTED DRAWING: None