The use of quinolones in respiratory tract infection (RTI) has developed from unpromising origins. A number of differing pathogens cause community‐acquired pneumonia (CAP), which is not a homogeneous clinical entity. Fluoroquinolones refer primarily to three currently available agents: levofloxacin, gatifloxacin and moxifloxacin. A recent comprehensive review of in vitro and ex vivo models of pneumococcal infection found most to indicate positive outcomes at AUC/MIC values of 20 to 50, thus explaining the paradox of certain fluoroquinolones, such as levofloxacin, which failed to attain AUC/MIC ratios in keeping with previously recommended levels (125 or greater) yet proved highly effective in human infection. Analysis of bacteriologic results according to specific pathogens has shown that the quinolones, in particular, agents such as levofloxacin, moxifloxacin, gatifloxacin, and gemifloxacin, are at least comparable with control drugs for the treatment of infections caused by Streptococcus pneumoniae, Haemophilus influenzae, and other common pathogens. Of the various community‐acquired RTIs, pharyngitis is one of the most common and carries a significant burden of illness. Of the infections described in this chapter, pharyngitis is the only one affecting the upper respiratory tract and it is responsible for 200 physician visits per 1,000 population annually. Acute bronchitis is primarily a viral or noninfective, pollution‐related entity which occurs in patients with normal airways and, as such, does not routinely justify antibiotic therapy.