Abstract: HH01(l-methyl-3,4,5,6,9, 10-hexahydro-7H-cyclopentaj,k-1,3-dioxolo4,5-h-pyrrolo2,1-b3-benzazepine) A and B in doses 30 mg· kg-l and 60 mg, kg-l wereshown to protect gastric mucosa of rats from damage induced by absolute ethanol , cold-immersionstress and pylorus ligation. No effect was found in indomethacin model in mice. HH01 was found todecrease secretion of gastric juice and HCI in pylorus ligated rats. The content of DNA in gastric juiceof animals treated with HH01 was lower than in control. The results suggest that HH01 is effective asan anti-ulcer agent , but its mechanism of action is yet unknown.