The blocking effects of a newly synthetized compound N-decyltropine bromide (IEM-1556), on pentagastrin-, carbachol- and histamine-induced gastric secretion in chronic dogs, on stress-induced changes in gastric mucosa in rats, on vagus-induced effect in heart and on arterial blood pressure in rats were studied. The effects were compared with those produced by hexamethonium, a conventional ganglionic blocking agent. IEM-1556 inhibited gastric secretion and acid output for a much longer time than hexamethonium did. It also effectively protected gastric mucosa against stress-induced erosions and hemorrhages. IEM-1556 much more effectively blocked the vagus-induced reduction of the heart rate than hexamethonium did, and, in contrast to latter, did not reduce the arterial blood pressure. The results suggest that IEM-1556 is a highly selective blocking agent for parasympathetic and enteric ganglia versus sympathetic ganglia.