Provided is a liquid composition for treating stomatitis, the liquid composition including: an epidermal growth factor; an adhesive polymer; and at least one stabilizer selected from the group consisting of ethylenediaminetetraacetic acid (EDTA) and salts thereof, histidine, lysine and inorganic acid salts thereof, arginin and inorganic acid salts thereof, and dextran. The liquid composition includes a stabilizer selected from EDTA (or salts thereof) and a certain amino acid (or inorganic acid salts thereof) and thus, physicochemical and biological stability of the epidermal growth factor can be substantially increased. Thus, the liquid composition can be stored and distributed for a long period of time. The stabilized composition includes an adhesive polymer, and thus, when ejected in a spray form in the mouth of a user, the liquid composition can be quickly attached to an inflammation site and exhibits effectiveness for a long period of time.