Chaga mushroom (Inonotus obliquus), a white rot fungus, belongs to the hymenochaetaceae family of Basidomycetes. Chaga mushroom grows on birch trees in colder northern climates. Since the sixteenth century, Chaga has been used as a folk medicine in Russia and western Siberia. Recently, many polyphenolic compounds including triterpenoids, steroids, and ergosterol peroxides from Inonotus sclerotia have shown various biological activities, including anti-bacterial, hepato-protective, and anti-tumor[5–7] effects. However, its molecular mechanisms to the anti-tumor effects have not been well documented, in spite of its increasing usage.