Acute lower respiratory tract infections in children are a worldwide public health problem, with an estimated 4 million potentially preventable deaths every year. Until recently, penicillin and related drugs were the treatment of choice for empiric therapy of paediatric lower respiratory tract infections. However, concerns over the emergence of penicillin-resistant strains of Streptococcus pneumoniae and beta-lactamase-producing strains of Haemophilus influenzae and Moraxella catarrhalis have led physicians to turn increasingly towards alternatives, such as the third generation cephalosporins. The oral extended spectrum cephalosporin cefpodoxime proxetil is highly active against the bacterial pathogens commonly associated with childhood lower respiratory tract infections. In order to evaluate its clinical efficacy in children with acute febrile lower respiratory tract infections, an international, multicenter, comparative, randomized open study was conducted in children ages 3 months to 11.5 years. Of 348 cases enrolled, 234 were randomized to cefpodoxime proxetil (8 mg/kg/day twice daily) and 114 to amoxicilin/clavanulate (amoxicillin 40 mg/kg/day 3 times a day). The duration of treatment was 10 days. Pretreatment diagnosis was pneumonia in 292 patients, bronchiolitis in 19 patients and acute bronchitis in 37 patients. Pathogens isolated from 59 cases included H. influenzae (47.5%), S. pneumoniae (23.7%), M. catarrhalis (11.9%) and Haemophilus parainfluenzae (6.8%). Clinical efficacy was evaluable in 278 children at the end of treatment when 95.2% of patients in the cefpodoxime proxetil group and 96.7% of patients in the amoxicillin/clavanulate group showed a satisfactory clinical response (cured or improved). The improvement was sustained at the follow-up visit, 10 to 20 days after completion of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)