Anti-ulcer activity of licorice alkaloid fraction, separated from Glycyrrhiza glabra L. by fractionation according to general alkaloid purification procedure, were studied with various experimental gastric ulcers. In Shay ulcer, licorice alkaloid fraction inhibit significantly response rate and severity of ulcer. But there was no significant changes in volume and pH of gastric contents. A male rat was fixed on a board and immersed up to breast in water of 25˚C for 20 hrs. Hemorrhage and erosion develop in all the animals on the mucosa of the glandular portion of stomach. Licorice alkaloid fraction (5 mg/kg, 10 mg/kg) inhibit significantly in the severity of stress ulcer but there was no changes in the response rate. Chlorpromazine produce marked inhibition in the severity and response rate of ulcer It was suggested that at least the anti-ulcer activity of licorice alkaloid fraction was not mediated by central depression.