Activated carbon characteristically shows an extremely high transmigration to the lymph node, as well as a sustained release of the adsorbed drugs. Therefore, several attempts to use activated carbon as a carrier in cancer chemotherapy have been done. In the present study, we first introduced a new drug-dosage form of cisplatin (CDDP) adsorbed to activated carbon particles (CDDP-CH), and examined its characteristics and anti-cancer effect against human bladder cancer cell lines. CDDP solution of varied concentrations (Randa) was mixed with activated carbon particles (Norit A) and examined for adsorption and discharge by atomic absorption spectrophotometry and high performance liquid chromatography. Total CDDP adsorption increased in proportion to the amount of activated carbon. CDDP-CH was successfully prepared at an efficient concentration for cancer chemotherapy and CDDP-CH slowly discharged CDDP, indicating it as a useful means for the anti-cancer drug. Using cultured human bladder cancer cell lines (KU-1, HTB9), the anti-cancer effect was compared between CDDP and CDDP-CH by MTT-assay and double layer soft agar colony assay. CDDP-CH revealed an inhibitory effect against human bladder cancer cell lines. In view of the fact that activated carbon readily migrates to the lymph node, clinical application of this drug dosage form may be useful in cases of malignant tumor metastasis to the lymph node.