This invention relates to a composition comprising ubiquinone having superior dispersion-stability in an aqueous solution and high bioavailability. The ubiquinone(s) is dispersed and emulsified in an aqueous solution of a water-soluble material in the presence of an organic acid(s) to form a protective colloid, the average particle size of the suspended particles being not more than 5 m. The liquid composition can be adsorbed in or carried on an excipient, or dried.