Ulmi pumilae Cortex(bark of Ulmus pumila L.), oriental medicine, has been used for the folk remedy of the gastric diseases. In order to investigate antiulcer activities, some experiments for Shay, aspirin-induced and indomethacin-induced gastric ulcers were conducted. The water extract of Ulmi pumilae Cortex(UX) was given intraperitoneally, and the groups of UX 500 and 1,000mg/kg significantly inhibited Shay, aspirin and indomethacin-induced ulcers in rats.