Laidlomycin is a polycyclic polyether antibiotic which possesses an inhibitory activity against various mycoplasma species}, and is effective in controlling coccidiosis in chickens. It is also known as selectively inhibiting the migration of hemagglutinin glycoprotein from Golgi apparatus to the cell surface in measles virus). Laidlomycin inhibited growth of some Gram-positive bacteria only at high concentrations such as 50-100 ug/ml, but was not active against Gram-negative bacteria, yeast and fungi even at concentration of 1,000 ug/ml. In broth dilution, laidlomycin was active against several illycoplasmas and most active against the sterol-nonrequiring mycoplasma, Acholeplasma laidlawii. Under the brand name Cattlyst Laidlomycin is indicated for improved feed efficiency and increased rate of weight gain in cattle fed in confinement for slaughter.