Levofloxacin has consistently been shown to have excellent activity against S. pneumoniae, and this has not changed significantly in the last few years despite extensive use. Even in the Far East, where levofloxacin has been available for a long time, it remains highly active, more than any other oral agent against this important pathogen. Levofloxacin is also 99-100% active against M. catarrhalis and H. influenzae, and covers the major atypicals, such as Mycoplasma pneumoniae and Chlamydia pneumoniae (3). Levofloxacin also has activity against methicillin-sensitive Staphylococcus aureus, an important complicating organism associated with persisting chronic infection.