Four short-term in vivo and in vitro tests were used to further confirm the antitumor activities of MCP, a vegetable powder, prepared from Malru crispo L. (i) In the H22 hepatoma-transplanting test, MCP had antitumor action, but MCP residue did not show such action; 5-FU appeared to have more potent antitumor activities and more harmful effects than MCP. (ii) In the micronucleus (MN) test, MCP significantly decreased MN frequency. (iii) In the cancer cell culture systems, the MCP fat-soluble extract revealed inhibitory effects on the growth and proliferation of the human hepatoma and the gastric cancer cells in a dose-response manner. (iv) In the colony formation test, MCP also altered the morphology of human gastric cancer cells. It was suggested that MCP could be consumed not only by healthy subJects for cancer prevention but also by patients with cancer as supplernentary treatrnent in combination with anticarcinogenic drug such as 5-FU, cyclophosphamide (CP) Four short-term in vivo and in vitro tests were used to further confirm the antitumor activities of MCP, a vegetable powder, prepared from Malru crispo L. (i) In the H22 hepatoma-transplanting test, MCP had antitumor action, but MCP residue Did not show such action; 5-FU appeared to have more potent antitumor activities and more harmful effects than MCP. (ii) In the micronucleus (MN) test, MCP significantly decreased MN frequency. (iii) In the cancer cell culture systems, The MCP fat-soluble extract revealed inhibitory effects on the growth and proliferation of the human hepatoma and the gastric cancer cells in a dose-response manner manner. (iv) In the colony formation test, MCP also altered the morphology of human gastric cancer cells. It was suggested that MCP could be not not only healthy subJects for cancer prevention but also was patients with cancer as supplernentary treatrnent in combination with anticarcinogenic drug such as 5-FU, cyclophosphamide (CP)