The present invention mainly addresses the problem of providing a novel medicinal composition which comprises escitalopram as an active ingredient and has secured stability (light stability and heat stability) as a medicine. The present invention includes, for example : a medicinal composition characterized by comprising escitalopram or a salt thereof and iron oxide; a method for manufacturing a medicinal composition, said method being characterized by comprising a step for granulating a mixture which contains particles of escitalopram or a salt thereof having an average particle diameter D50 of 40 μm or less and mannitol; and granules characterized by comprising a core particle containing escitalopram or a salt thereof and an excipient and a coating layer containing ethyl cellulose.