Purpose: Infections of the lower respiratory tract pose an important problem in nursing homes. Despite the magnitude of this problem, few, if any, antibiotic studies have been targeted specifically at nursing home-acquired bronchopulmonary infections. Following the establishment of a teaching Extended-Care Nursing Home Program, which facilitated the early diagnosis and therapy of bronchopulmonary infections, a comparative trial of oral ciprofloxacin and intramuscular cefamandole was initiated in elderly patients with lower respiratory tract infections. In addition to assessing the relative efficacy and safety of ciprofloxacin and cefamandole, our goals were to identify problems and pitfalls associated with conducting clinical research in this nursing home setting, evaluate selected clinical and laboratory features of lower respiratory tract infection in this patient population, and measure outcomes in all study groups. Patients and methods: During a 20-month period, 40 patients with pneumonia and 20 patients with acute bronchitis were enrolled in this randomized study. Sixty-three patients with pneumonia who were ineligible for the randomized study were also followed prospectively. The mean age of the 111 participants (123 cases) was 80.8 years; all patients had at least one chronic medical condition. Results: Although Streptococcus pneumoniae was the single most common isolate, gram-negative bacteria were cultured from 81 percent of the cases that yielded pathogens from a satisfactory sputum specimen. The in-hospital mortality rate was strikingly low (6.5 percent), and a large majority of patients in all study groups were discharged safely back to their nursing homes well within the Diagnosis-Related Group length of stay. Conclusion: Ciprofloxacin appeared to be as safe and effective as cefamandole in this nursing home program; however, additional studies are needed to determine its role in the treatment of elderly patients with bronchopulmonary infections.