Novel quinazolino-1,4-benzodiazepin-5,13-diones, which have been found to be antagonists of the function of cholecystokinins (CCK), to the preparation of these compounds from compounds prepared by aerobic fermentation of certain Aspergillus alliaceus strains, and to the use of these compounds to antagonize the function of CCK, which antagonism is useful, e.g., for the treatment and prevention of disorders of the gastrointestinal, central nervous and appetite-regulatory systems of mammals, especially of humans.