The structures of sporaricins A and B have been determined to be 2-amino-1-O-(2,6-diamino-2,3,4,6,7-pentadeoxy-beta-L-lyxo-heptopyranosyl)-2,3,5-trideoxy-5-(N-glycyl-N-methyl-amino)-4-O-methyl-D-chiro-inositol and 2-amino-1-O-(2,6-diamino-2,3,4,6,7-pentadeoxy-beta-L-lyxo-heptopyranosyl)-2,3,5-trideoxy-4-O-methyl-5-methylamino-D-chiro-inositol, respectively.