Is whiskey bad for ulcer ?

If you have ongoing peptic ulcer disease which is not in remission, nor controlled with appropriate medication, whiskey can indeed be very irritating, and perhaps will exacerbate symptoms dramatically. Make certain that all is stable prior to indulging in strong alcoholic beverages. Get clearance from your gastroenterologist.

Yes. Alcohol is a poison that never did anybody any good, ever, so stay away from it. It will destroy your brain cells, damage testicular cells that make testosterone, facilitate development of cancer in many organs, cause hepatitis, cirrhosis and pancreatitis etc. There is no safe level of alcohol intake. Quit while you are ahead.