A randomised, double-blind study of adults with community-acquired pneumonia (CAP) resulted in clinical cure rates of 90.0% for telithromycin and 94.2% for trovafloxacin. Bacteriological eradication rates were also comparable for both treatments. All high-risk patients (i.e. > or = 65 years old [n=25], Pneumonia Severity Index score > or = 111 [n=16], pneumococcal bacteraemia [n=4]) were clinically cured. In infections caused by Mycoplasma pneumoniae and Chlamydophila (Chlamydia) pneumoniae, clinical cure rates were 93.3% (14/15) for telithromycin and 100% (16/16) for trovafloxacin. Possibly drug-related, treatment-emergent adverse events (TEAEs) were considered mild and occurred in 47.2% of telithromycin and 33.0% of trovafloxacin patients. The most frequently reported, possibly drug-related, TEAEs were diarrhoea and nausea for telithromycin and diarrhoea and headache for trovafloxacin. Serious TEAEs occurred in 1.9% of telithromycin and 1.8% of trovafloxacin subjects and were considered not drug related. No deaths occurred during the study. Telithromycin and trovafloxacin were safe and comparable in efficacy in these patients with CAP.