Objective: This study was carried out to investigate the effects of Hyangsayukgunja-tang extract on indomethacin-induced gastric mucosal lesions of mice. Methods: To evaluate the effects of Hyangsayukgunja-tang extract and Misoprostol, the morphology of gastric mucosa, and the distribution of mucose cells, PNA(Peanut Agglutinin), ICAM(intercellular adhesion molecule), and apoptotic cells were observed. Hyangsayukgunja-tang extract and Misoprostol were intragastric injected to the test groups at hour 72 before and just before indomethacin treatment(HYT-J, HYT-72, M-J, M-72), while the INDO group was injected only with indomethacin and the control group was subcutaneously injected only with saline. Results: The gastric mucosal lesions incresed in the fundus and body of INDO group, but softened in HYT group and M group, the effects were more excellent in the HYT-72, M-72 groups than the HYT-J, M-J groups and in the HYT group than M group. The disappearance of surface and neck mucose cells were shown in INDO group, but softened in HYT group and M group. The mucosal configuration of HYT-72 group was the same as control group. The numerical increase of PNA positive reaction in cytoplasm of perietal cells were appeared in INDO group. The PNA positive reaction in HYT group and Miso-group were shown in surface mucous cells and microvilli of apical surface in chief cells as control group, and were the same as control group in all mucosa of HYT-72 group. The distribution of ICAM positive cells, increased in INDO group, but decreased in M-72 group, and were the same as control group in HYT-72 group. The apoptotic cells, increased noticeably in gastric mucosa of INDO group, decreased in HYT group and M group, and decreased noticeably in HYT-72 group. Conclusions: Hyangsayukgunja-tang extract had excellent effects on indomethacin-induced gastric mucosal lesions.