Flavorings in Electronic CigarettesAn Unrecognized Respiratory Health Hazard?

This Viewpoint examines the flavorings added to e-cigarettes and the potential respiratory risks they may pose. Use of electronic cigarettes (e-cigarettes), vape pens, e-hookah, e-cigars, e-pipes, or other electronic nicotine delivery systems (ENDS) has increased rapidly since their introduction in the United States in 2007, growing to a $2 billion market.1 There is controversy concerning the utility of ENDS as a harm reduction strategy, reflecting major gaps in the emerging evidence on potential benefits and harms of the products.