PURPOSE: TO provide an anti-arteriosclerotic agent capable of suppressing the hyperplasia of the arterial smooth muscle cells, containing, as active ingredient, an estrogen derivative.

CONSTITUTION: This anti-arteriosclerotic agent contains, as active ingredient, a compound of formula I (X is of formula II, etc., R1 and R2 are each H or an acyl such as acetyl or propionyl) which is a metabolite of estrogen as female hormone or a prodrug capable of easily forming 2-methoxyestrogen in vivo and subject to deacylatior in vivo. The compound of formula I is low-toxic, presents no hormonal action, being capable of lowering serum lipoperoxide levels leading to migration of the smooth muscle cells in the intermediate membrane of arterial wall into the inner membrane and preventing the cells from proliferation to cause angiopathy. This agent can be made into a preparation such as a oral agent, injection or percutaneous agent, and its dose is pref. 0.5-10mg/kg b.w./day once or twice a day.