Abstract: OBJECTIVE To investigate the influence of Mongolian patent medicine Anari-4 to gastric ulcer induced by alcohol and stress reaction in mice. METHODS Gastric ulcer models were established by alcohol and stress reaction, respectively. The ulcer index, the contents of superoxide dismutase (SOD), nitric oxide (NO) and malondialdehyde (MDA), pathological sections were measured, respectively. RESULTS Compared with model group, Anari-4 (0.025, 0.05, 0.1 g·kg^-1) significantly increased the contents of SOD and NO in gastric ulcer induced by alcohol (P<0.05). Anari-4 (0.05 g·kg-1) significantly decreased the content of MDA (P<0.05). Anari-4 (0.025, 0.05, 0.1 g·kg^-1) significantly decreased the ulcer index(P<0.05). The inhibitory rates were 13.4%, 28.1% and 59.2%, respectively. Compared with model group, Anari-4 (0.025 g·kg^-1) significantly increased the contents of SOD in gastric ulcer induced by stress reaction (P<0.01). Anari-4 (0.05 g·kg-1) significantly decreased the content of MDA (P<0.05). Anari-4 (0.025, 0.05, 0.1 g·kg^-1) significantly increased the content of NO and decreased the ulcer index(P<0.01). The inhibitory rates were 31.4%, 51.0% and 44.3%, respectively. CONCLUSION Anari-4 plays a protective role against gastric ulcer. Its antiulcer effect is related to inhibiting generation of oxygen derived free radicals, and decreases the content of NO.