Owing to its peculiar pharmacological characteristics, paclitaxel attains substantial intra-peritoneal concentration for a prolonged period when delivered intra-peritoneally, and is active against peritoneal metastasis of ovarian cancer. It is also considered promising against disseminated gastric cancer. However, the fact that the intra-peritoneal paclitaxel has not been approved in Japan has rendered its evaluation by a formal clinical trial impossible. The authors designed a randomized phase II trial using the Kodo Iryo Hyoka system, a new system to legally test an yet unapproved mode of treatment. It is hoped that this trial will result in a breakthrough in the treatment of peritoneal carcinomatosis from gastric cancer.