Rosamaricin is a macrolide antibiotic similar to erythromycin. This compound is more effective against Gram-negative bacteria than erythromycin, especially in the prostate where rosamaricin was shown to be more concentrated than erythromycin in dogs. Rosamaricin has antibiotic activity against Neisseria gonorrhoeae, Chlamydia trachomatis, Ureaplasma urealyticum and Mycoplasma hominis. When the drug was compared with penicillin G in the treatment of pneumococcal meningitis in rabbits it was found to be less effective than penicillin G, as measured by bacterial clearance from cerebrospinal fluid and by treatment outcome. No information on the current use of this compound is available.