Abstract: New pyridobenzodiazepinones of the formula ##STR1## are described wherein X represents oxygen, --NH-- or --NCH.sub.3 -- and R represents 1-methyl-4-piperidinyl or 4-methyl-1-piperazinyl group optionally substituted by a methyl group, or a 3.alpha.- or 3.beta.-tropanyl group, and the nontoxic pharmaceutically acceptable acid addition salts thereof. The specification also describes processes for preparing these compounds, pharmaceutical compositions containing these compounds and new intermediate products used in preparing them.The compounds of formula I have antiulcerative effects and an inhibitory effect on gastric acid secretion, without the side effects such as dryness of the mouth and mydriasis which occur with other substances having an anticholinergic activity.