Propylene glycol may be safe to eat, but its toxic to inhale. Inhaling this toxic e cigarette liquid ingredient can lead to lung inflammation and higher risk of respiratory disease. Lactate dehydrogenase (LDH) levels indicating toxicity of E cigarette Download Scientific Diagram Meilleur E liquide Menthe et Menthol Fracheur Intense et Hit Hidden Formaldehyde in E Cigarette Aerosols New England Journal of Medicine Inhalation toxicity of thermal transformation products formed from e cigarette vehicle liquid using an in vitro lung model exposed at the Air Liquid Interface ScienceDirect