What are e-cigarettes?

E-cigarettes are battery-powered devices that work by heating a liquid into an aerosol that the user inhales and exhales. The e-cigarette liquid typically contains nicotine, propylene glycol, glycerin, flavorings, and other chemicals. Nicotine is the addictive drug found in regular cigarettes and other tobacco products. Research shows that e-cigarette aerosol often contains substances that can be harmful, including flavoring chemicals (like diacetyl, which is linked to lung disease), metals (like lead), and other cancer-causing chemicals.