To obtain a composition having an excellent action of activating fibroblast growth factor by using, as the effective constituent, a sulfuric ester of N- acetylneuraminic acid homopolymer or a pharmaceutically allowable salt thereof.

This composition contains as the effective constituent a sulfuric ester of N-acetylneuraminic acid homopolymer, represented by the formula (wherein R is H or SO3H; n is 5 to 1,000; and the degree of sulfation is 0.5 to 3), or a pharmaceutically allowable salt thereof. The sulfuric ester is produced by forming a free acid from sodium N-acetylneuraminate (or colominate) with a cation-exchange resin, reacting the free acid with tributylamine to form tributylamine salt of N- acetylneuraminic acid, and reacting the salt with a sulfating agent comprising, e.g. SO3-pyridine complex in a solvent such as dimethylformaldehyde at a temp of 0-100°C. The pharmaceutically allowable salt comprises the salt of an alkali metal such as sodium or potassium, or the salt of an alkaline earth metal such as calcium.