a pharmaceutical composition for the treatment of peptic ulcer which contains 2 - n - methyl - 1 , 2 , 3 , 4 - tetrahydro - 9h - dibenzo -- pyridinocycloheptatriene or its pharmaceutically acceptable salt as an active ingredient in association with a pharmaceutically acceptable carrier , and a method for treating peptic ulcer by administering the said compound , mo - 8282 . the said compound exhibits high efficacy in the treatment of peptic ulcer and has low toxicity .