Antacid(AM, 600 mg/kg=aluminium hydroxide, magnesium hydroxide, and simethicone with a ratio of 1 : 1 : 0.1) and aceglutamide aluminium(AGA, 263 mg/kg)-Effect of the combined preparation containing on the gastric mucosal hexosamine, sialic acid, and aluminium contents adhered to the gastric wall of the rat was investigated. Severe ulcers were produced in rats by injecting of $30;{mu}l$ acetic acid(30%) into the subserosal layer of one position in the corpus. When given orally for 15 consecutive days, AM(1,200 mg/kg), AGA(525, 1,050 mg/kg), and the combined preparation significantly decreased the ulcer area. AGA(525, 1,050 mg/kg) and the combined preparation also increased the amount of hexosamine and sialic acid in the intact and ulcerated areas. On the other hand, the contents of hexosamine and sialic acid were not affected by AM (600, 1,200 mg/kg). The amount of aluminium adhered to the gastric wall of the rat was higher in the combined preparation when compared to the AM(600 mg/kg) and AGA(263 mg/kg). The aluminium contents adhered may play an important role protecting mucosa from aggresive action of gastric juice and potenting defensive factors through the increase of mucosa-forming components by AGA.