Abstract: Studies on the drug release in vitro and hepatic arterial chemoembolization in rivo were carried out with the newly developed CDDP—PLA microspheres. The mechanism of the in vitro release was shown to conform to Higuchi equation. After chemoembolization the CDDP—PLA microspheres showed remarkably lower CDDP concentrations in the general circulation and much higher concentrations in the hepatic tissue e. g. up to 21.55±12. 18 μg/g at 8 h, which is much higher than that (3. 16±0. 09 μg/g) of the CDDP in hepatic arterial infusions. Thus, the CDDPPLA microspheres may improve the curative effects and lower the side effects, especially the kidney toxicity, of the anticancer drug cisplatin.