A solid oxidized glutathione salt is produced by heating oxidized glutathione to at least 30°C while bringing the oxidized glutathione into contact with an aqueous medium composed of water and/or a water soluble medium in the presence of a substance capable of generating at least one type of cation selected from ammonium cations calcium cations and magnesium cations so as to produce a salt of the oxidized glutathione and the cation as a solid.