PURPOSE: To provide an antiulcer agent containing vitamin A acid zinc salt as an active ingredient, having a strong antiulcer action, capable of being applied for a long period, and not causing a side effect.

CONSTITUTION: The antiulcer agent contains vitamin A acid zinc salt of the formula as an active ingredient. The vitamin A acid zinc salt is obtained by mixing vitamin A acid with a water-methanol mixture containing the same mole of potassium hydroxide with stirring, filtering off the vitamin A acid suspended and floated in the non-reacted solution, and subsequently dropping the obtained filtrate on a water-methanol mixture containing zinc nitrate in an amount of 1.0-1.1 equivalent based on the vitamin A. The vitamin A zinc salt is administered at a dose of 25-500mg, preferably 50-100mg, for an adult a day.