An angucycline series compound P371 A1 (1) from Streptomyces sp. P371 was established to have a novel structure comprising an ureido group at one of four sugar units on the basis of 2D NMR techniques. 1 exhibited an inhibitory activity against the pentagastrin-stimulated acid secretion as well as protective activities against HCl/ethanol- and indomethacin-induced gastric lesions.