During the screening for new antitumor antibiotics, new members of the anthracycline group were discovered in culture broths of a strain designated as MG344-hF49 and classified as Streptomyces cyaneus, and they were named ditrisarubicins A, B and C. These antibiotics inhibit the growth of Gram-positive bacteria and prolong the survival period of mice bearing leukemia L-1210. Each ditrisarubicin consists of β-rhodomycinone, two molecules of rhodosamine and two to four other hexoses.