PURPOSE: To obtain an arterialization inhibitor containing a specific compound as an active ingredient, excellent in arterialization-inhibiting action, having low toxicity and capable of safely using and useful for preventing and treating diabetic retinopathy, chronic inflammation, psoriasis and arteriosclerosis.

CONSTITUTION: This inhibitor contains 3-hydroxymethyl-6-methoxy-8-hydroxy-1 H-2-benzopyran-1-one of the formula as an active ingredient. The compound of the formula is obtained by culturing, e.g. Streptoverticillium eurocidicum M-143-37Fl1 strain (FERM-BP-2783) and collecting the compound from the culture solution. The content of the compound of the formula is preferably 5-50wt.% based on the total composition when the inhibitor is a solid agent such as tablet and the content of the compound is usually preferably 0.1-10wt.% when the inhibitor is a liquid agent such as injection. Furthermore, the compound of the formula is preferably administered in a daily dose of 0.3-300mg/kg in the case of oral administration or 0.03-30mg/kg in the case of parenteral administration.