Our hypothesis is that 8 weeks of chlorhexidine oral rinse will decrease microbiota biomass compared to baseline and those on placebo. Furthermore, we hypothesize that chlorhexidine treatment will: i) decrease lung and oral microbiota diversity; ii) alter microbiota taxonomic composition in the lung and oral cavity; iii) decrease systemic inflammation as measured by blood high sensitivity C-reactive protein (hsCRP), fibrinogen and leukocyte count; and iv) demonstrate a trend towards improvement in respiratory health status as measured by the Breathlessness, Cough, and Sputum Scale (BCSS)[1, 2] and St. George's Respiratory Questionnaire (SGRQ).