Carbazomycin B is a bacterial metabolite found in Streptomyces with diverse biological activities. It exhibits activity against seven fungi, seven bacteria, P. falciparum, C. albicans, and five plant pathogenic fungi. Carbazomycin B is cytotoxic to MCF-7, KB, NCI H187, and Vero cells, and inhibits 5-lipoxygenase (5-LO) activity in RBL-1 cell extracts (IC50 = 1.5 µM).