Electronic cigarettes (ECs) have quickly gained popularity among adolescents and adults, and have begun to replace conventional cigarettes as a source of nicotine. Although little is known about the impact of the exposure of chemical constituents of ECs, two major constituents, propylene glycol and vegetable glycerin have been implicated as formaldehyde-releasing agents. The wide variety of EC flavours appeal to users of all ages with reports showing a positive correlation between EC use and sweet flavorings. In addition, although marketing strategies advertise ECs as tools to facilitate smoking cessation, the evidence supporting this role is weak. In terms of its effect on users with pre-existing cardiovascular diseases, the data is conflicting regarding whether ECs have an impact on cardiovascular function. Although it is obvious that their safety and efficacy needs to be better understood, it is nonetheless essential to review what the research conducted so far has shown.