In an open prospective study, the antidepressive effects of the selective and reversible MAO-A inhibitor, brofaromine, were investigated in nine endogenous depressed patients, who had failed to respond to cyclic antidepressants. In three patients a clinically relevant improvement was observed, although for the total group, no statistically significant treatment effect could be demonstrated. In two subjects, postural hypotension and sleep disturbances occurred temporarily.