PURPOSE: A carcinostatic having extremely high carcinostatic effect caused by the reinforcing action of liphopolysaccharide, obtained by combining a carcinostatic glucan derived from shiitake (mushroom) with liphopolysaccharide.

CONSTITUTION: A carcinostatic glucan derived from shiitake (e.g., carcinostatic active glucan obtained from a fruiting body of shiitake, hypha, or culture substance of shiitake, or carcinostatic substance prepared by modifying them chemically) is used in combination with liphopolysaccharide. The liphopolysaccharide is obtained from a Gram-negative bacillus, e.g., Escherichia coli, etc. by a method, e.g., extraction with water-hot phenol. The carcinostatic glucan liphopolysaccharide can be adminstered by injection in a state of mixture, or applied separately by injection. The use of a liphopolysaccharide having carcinostatic activity exhibits extremyly high synergistic effect.