Maduramicin is a polyether antibiotic first isolated from Actinomadura yunnaense (formerly Nocardia sp. X-14868) in 1963. Maduramicin is a broad spectrum anticoccidial also active against Treponema and Cryptosporidium. Maduramicin is an ionophore, forming complexes with monovalent cations, with a higher affinity for K+ than Na+. Maduramicin is used as the ammonium salt in animals to prevent coccidiosis and to promote growth.