Stabilization of w/o/w emulsion and its application to transcatheter arterial embolization (TAE) therapy are reviewed. W/o/w emulsion was stabilized by making inner aqueous phase hypertonic, addition of chitosan in inner phase, and techniques of phase-inversion with porous membrane. Lipiodol w/o/w emulsion for TAE therapy was prepared by using a two-step pumping emulsification procedure. The procedure is so easy that the emulsion could be prepared even during the surgical operation. The deposition after hepatic arterial administration of the emulsion was detected by an X-ray CT scanner. The concentration of epirubicin hydrochloride (EPI) in liver was increased and its residence was prolonged by encapsulating it in the w/o/w emulsion. The toxic effects of EPI and lipiodol on the normal hepatic cells were reduced. The w/o/w emulsion prepared by us is a suitable formulation for the TAE therapy.