This study was conducted to further purify and characterize a polysaccharide fraction from whole parts of Duchesnea indica (Andr.) Focke, which was previously reported to show an antitumor activity by us. Mild acid-treatment of the fraction by 5% acetic acid yielded three subtractions (Fr. A,B and C) on a Sephadex G-25. Fr. A was composed of uronic acid, hexose, pentose and phenolic substance, Fr. C mainly phenolic substance, and Fr. B contained hexose. All three fractions exhibited colony stimulating factor activity.