Abstract: A foodstuff capable of preventing the induction or metastasis of cancer is provided. In particular, an Agaricus blazei Murill extract comprising an ingredient capable of preventing the induction or metastasis of cancer is provided. The ingredient can be a chromatographic main elute fraction of 100 to 2000 molecular weight, obtained by the steps of extracting the fruit body of Agaricus blazei Murill with hot water, dialyzing the resultant extract, and subjecting the thus obtained dialysis external fluid to chromatography. Alternatively, the ingredient can be a dialysis external fluid obtained by the steps of extracting the fruit body of Agaricus blazeiMurill with hot water, adding ethanol to the resultant extract to thereby obtain precipitates, dissolving the precipitates in water, and dialyzing the solution.