Pharmacologically, blocking cAMP degradation has the potential of restoring ethanol-suppressed cellular cAMP levels and therefore epithelial functions. This finding is of clinical implications. Phosphodiesterase inhibitors such as papaverine may improve mucociliary clearance in alcoholics by enhancing airway epithelial ion secretion and ciliary beating. Moreover, enhancement of airway epithelial ion secretion alters the composition of ASL. Our laboratory has reported that extracellular chloride levels affect neutrophil microbial killing ability [45] . Thus, increasing ASL chloride level by phosphodiesterase inhibitors may also improve phagocytic innate immunity in airways of alcoholics.