PURPOSE: To provide an antiulcer agent exhibiting excellent drug action especially against stress ulcers, by using a specific compound known as a cyanine- type photosensitive dye and remedy for frostbite and scald as an active component.

CONSTITUTION: A compound of formula (R is H or 1W4C alkyl; X is halogen) is used as an antiulcer agent. A concrete example of the compound is 4,4'-{3-{2-[1-ethyl-4-( 1-H )quinolidene]ethylidene}}propenylene[bis(1-ethylquinoli nium iodide)]. It is administered preferably by oral administration at a dose of preferably 80W200μg/kg. The compound of formula exhibits high drug action as a remedy for central ulcer. The compound can be produced by reacting aniline with methyl vinyl ketone to obtain lepidine, separately preparing a diformyl derivative of the compound of formula by Vilsmeier reaction, reacting the derivative with the above-obtained lepidine and reacting the reaction product with desired alkyl halide.