Abstract: A therapeutic agent for interstitial pneumonia is provided which effectively exploits the effect of superoxide dismutase (SOD). The therapeutic composition for interstitial pneumonia contains 10 to 100 mg of lecithinized superoxide dismutase represented by the following general formula (I): SOD?(Q-B)m ??(I) (wherein SOD? is a residue of superoxide dismutase; Q is a chemical crosslink; B is a residue of lysolecithin having the hydrogen atom of the hydroxyl group at position 2 of its glycerol moiety removed; and m is the average number of lysolecithin molecules bound to one molecule of the superoxide dismutase and is an integer of 1 or greater) and further contains sucrose to give it a stable form suitable for intravenous administration.