E-cigarettes, or electronic nicotine delivery systems, are popular among smokers who are looking for a less harmful alternative to conventional tobacco, and the use of e-cigarettes is affected by existing tobacco control policies. E-cigarettes, which are electronic devices designed to allow the user to inhale nicotine as a vapor, are controversial in terms of their harm reduction claims as it can undermine existing tobacco control policies and has the potential to re-normalize smoking behavior. Currently, many of the chemicals used in e-cigarettes have not been comprehensively disclosed, and there is no adequate data on their emissions. Furthermore, the benefits of e-cigarettes have not been adequately shown. To date, a small number of studies have evaluated e-cigarettes as a harm reduction and cessation aid and have found conflicting findings. Meanwhile, e-cigarette or vaping product use associated lung injury has been identified, and an increased use of e-cigarettes in the youth has also been reported recently in the United States. These raise a great social concern around how to regulate e-cigarettes for the protection of public health. A range of current and proposed legislative and regulatory options exists. Some countries have banned e-cigarettes entirely, while others are ready to regulate e-cigarettes as a type of medicine. A lack of consensus on whether e-cigarettes facilitate or threaten existing tobacco control strategies is driving a discussion on how to regulate e-cigarettes in terms of the protection of public health.