E-cigarettes have become popular and widely used so fast that the safety testing on them is practically non-existent. While researchers rush to define the toxicities and potential health effects of e-cigarettes, should we be advising everyone against these nicotine delivery devices? Or should we try to be positive and hopeful, in case e-cigarettes have fewer adverse health effects relative to conventional tobacco cigarettes, and thus advise current smokers to switch to e-cigs as a harm reduction strategy? Beyond that, what are the risks of the different e-cig flavors and types of devices? Is vaping caffeine and THC more or less dangerous than vaping nicotine? What are the specific dangers of e-cig use for children, teenagers and young adults? Laura E. Crotty Alexander, MD examines the evolution of e-cigarettes and and shares a physician’s view.