Present invention provides a bioactive fraction of Anisomeles indica, TSYI-813, and its preparation which includes extracting Anisomeles indica using an alcohol solvent, fractioning the extract of Anisomeles indica by an organic solvent and water, and purifying via a silica column chromatography with 10:1˜10:5 hexane/ethyl acetate for sequential elution to give the bioactive fraction of Anisomeles indica, TSYI-813. The bioactive fraction of Anisomeles indica, TSYI-813, disclosed in present invention can can be used as an effective ingredient for treating or improving gastric ulcers, including reducing the area of ulcer and inflammation in the stomach tissue.