Disclosed is an adjuvant that has an anti-tumor effect and that is used in an ancillary manner with a cancer treatment agent. Specifically, disclosed is an adjuvant that has an anti-tumor effect and that, separately from a cancer treatment agent such as an anti-cancer agent, can cause the effect of the cancer treatment agent to be expressed more effectively. The adjuvant having an anti-tumor effect is formed from eliminating iron from a clinical nutritional supplement and/or a nutritionally balanced food. Separately from the cancer treatment agent such as an anti-cancer agent, by providing an iron chelating agent or a clinical nutritional supplement and/or a nutritionally balanced food that do not contain iron, iron in the blood serum is decreased, and thus it is possible to suppress the actual growth of a tumor, and simultaneously to facilitate angiogenesis.
