[en] The chemoembolization with Lipiodol and doxorubicin hydrochloride is used in patients with hepatocellular carcinoma. What condition is the ideal emulsion of Lipiodol and doxorubicin for excellent anticancer effect? Microscopic evaluation was performed on the emulsions, which were varied with different specific gravities of doxorubicin solutions, degrees in mixing of the emulsion, and amount of Lipiodol. 1. Maximal amount of doxorubicin solution was contained in Lipiodol droplets and the release of doxorubicin from the droplets were delayed, when specific gravity of doxorubicin was equal to that of Lipiodol (SG,1.28). 2. The optimal therapeutic ratio of Lipiodol and doxorubicin was 3 : 2 at least, as in the emulsion less than 3 : 2, unmixed free forms of doxorubicin solution were increased. 3. The emulsion mixed by pumping 50-100 times had smaller Lipiodol droplets and contained larger amount of doxorubicin solution in the droplets than by pumping 20 times. We recommended the emulsion with specific gravity of doxorubicin equal to Lipiodol (SG,1.28), the ratio of Lipiodol and doxorubicin close to 3 : 2, and the mixture prepared with pumping 50-100 times