Fosfomycin has been tested in 25 adult patients with bronchial or bronchopulmonary acute processes, of which 13 were simple acute processes of a greater or lesser severity, and 12 acutenesses of chronic bronchial processes. The germs found most frequently in the sputum cultures were Streptococcus pneumoniae and Klebsiella. Fosfomycin was used intramuscularly with doses of 4 g/day, for an average of 10 days. The results obtained were 16 cures, 7 improvements and 2 failures, which represents 92% success with 8% failures.