We examined the effects of Whadamcheongwha-tang(WDCWT) extract on the acetic-acid induced antigastric ulcer in rats. These experiments investigated the numerical changes of gastrin and histamine secreting cells of the gastric mucosa by immunohistochemical method, and the changes of mucin of gastric mucosa by PAS-AB stain methods after the oral administration of WDCWT extract(1.0ml/day) and omeprazole(0.2mg/day) for 1, 3 and 6 weeks. The result are as follows; 1. When WDCWT extract was administrated for 1, 3, 6 weeks, in result, gastrin secreting cells in gastric mucosa were increased compared to the control group. 2. When WDCWT extract was administrated for 1, 3, 6 weeks, in result, the density of immunoreactive gastrin cells was increased compare to the control group. 3. When WDCWT extract was administrated for 1, 3, 6 weeks, in results, the changs of mucosal thickness stained by PAS/PAS-AB was increased compared to the control group. 4. When WDCWT extract was administrated for 1, 3, 6 weeks, in results, the density of PAS stain was decreased compare to control group, but density of AB stain was increased compare to control group. The results suggest that WDCWT extract inhibits a gastric acid secretion in rat gastric mucosa, and is useful in the treatment of the hyperacidity and gastric ulcer.