Background: In recent years, fluoroquinolone research has focused on achieving several goals, including (1) enhanced potency against gram-positive cocci, notably Streptococcus pneumoniae, and anaerobes, while (2) maintaining potency against gram-negative pathogens, (3) optimizing pharmacokinetics and pharmacodynamics (PK/PD), and (4) minimizing potential adverse drug reactions through recognition and avoidance of structural configurations that have characterized earlier, reactive compounds. Objective: This review examines the efficacy and safety of fluoroquinolones and the specific clinical evidence regarding levofloxacin. Methods: Using published literature collected over time by the author, a review was conducted, focusing on the efficacy and safety profile of levofloxacin and other fluoroquinolones. Results: The newer fluoroquinolones have fulfilled many of the research goals described above. Levofloxacin has improved anti-gram-positive potency, PK/PD properties, a proven clinical trial record (particularly for community-acquired pneumonia [CAP]), and an excellent safety profile-in the context of the treatment of >250 million patients worldwide in the past decade. It is licensed for management of drug-resistant S pneumoniae infections in the United States and has gained widespread formulary acceptance and guideline inclusion. Studies assessing levofloxacin for CAP therapy show significant advantages over standard therapy, such as trends toward reduced IV therapy and length of hospitalization, reduced mortality, and significant associated cost reduction. In addition, levofloxacin has proved highly effective in acute exacerbations of chronic bronchitis (AECB), with excellent clinical and bacteriologic results, typical of the class, and significant advantages-in terms of clinical response, overall pathogen eradication, extension of the symptom-free period, and trends toward a reduction in the number of consultation visits and hospitalizations-over standard agents, such as the oral cephalosporins. Conclusions: Levofloxacin offers a combination of documented efficacy and tolerability, and provides an important option for the treatment of bacterial infections, including CAP and AECB, compared with standard agents used in the management of lower respiratory tract infections. Copyright (C) 2003 Excerpta Medica, Inc.