Similar DNA changes found in cells of both smokers and e cigarette users UCL News UCL University College London E cigarettes may not contain tobacco, but they still deliver nicotine, a highly addictive substance that can harm the developing brain, increase blood pressure, and lead to long term addiction. Many also contain toxic Sensation de liquide dans la bouche e cigarette, rmonte, dangereux E cigarettes aren't harmless, and combining them with cigarettes makes them even worse Study Summary