Provided are: a novel lactic acid bacterium strain which can inhibit the production of any volatile sulfur compound by a mouth bacterium, does not have a caries-producing property, does not cause infective endocarditis, and is safe in an oral cavity and a prophylactic, ameliorating and/or therapeutic agent for oral diseases and discomforts using the lactic acid bacterium strain.A prophylactic and/or therapeutic agent for oral diseases, comprising, as an active ingredient, at least one lactic acid bacterium which is selected from
