Selective delivery of a high level of Mitomycin C (MMC) in intraperitoneal disseminated lesions was studied using a new dosage form of MMC, called MMC-CH. Intracavitary MMC-CH delivered a much higher level of MMC selectively to intraperitoneal tissues, with a much lower level of MMC in the whole body, in comparison with MMC solution. The index [MMC level in the intraperitoneal organs]: [MMC level in blood] was much higher and increased with time in the MMC-CH group, but not in the MMC solution group.