In preclinical models, the inhalation of a mixture of living Lactobacilli bacteria attenuated pulmonary inflammation and improved lung function and structure for the chronic lung diseases bronchopulmonary dysplasia and chronic obstructive pulmonary disease. This study determined the mechanism of this live biotherapeutic product -- a powder mixture of living Lactobacilli bacteria -- to reduce neutrophilic inflammation and reduce a broad swath of inflammatory markers in BPD and COPD.