Almost all patients with gastrointestinal or ovarian malignancy die as a result of progression and/or recurrence in the peritoneal cavity. Although palliative systemic chemotherapy may succeed in improving the survival of patients with a particular type of cancer, almost all patients with ovarian and gastric cancers die from involvement of the abdominal cavity. In order to successfully treat such cases, new therapeutic technologies must be based upon an understanding of the mechanisms involved in intraperitoneal metastasis. This review discusses a novel anticancer drug-delivery system to control intra-abdominal metastatic foci, which exploits our understanding of intraperitoneal metastasis by relying on an oligomannose-coated liposome carrier that preferentially targets extranodal lymphoid tissue in the omentum.