Introduction: E-cigarettes or or electronic nicotine delivery systems (ENDS) have rapidly gained popularity in the U.S. Controversy exists about the safety and efficacy of ENDS. The American College of Preventive Medicine's Prevention Practice Committee undertook a consensus-based evidence review process to develop a practice statement for the American College of Preventive Medicine. Methods: A rapid review of the literature was performed through June 2017 to identify efficacy, patient-oriented harms, and the impact on population health. Results: On an individual level, limited evidence suggests that ENDS may be effective at reducing cigarette use among adult smokers intending to quit. There is insufficient evidence addressing potential long-term harms of ENDS, and limited evidence is available about short-term harms of ENDS and the impact of secondhand exposure. Although ENDS appear safer than combustible cigarettes, they are not without risk. Among youth there is no known benefit and significant concern for harm. On a population level, there may be significant harms associated with ENDS, particularly among youth nonsmokers. The long-term balance of potential benefits versus harms from the individual and population perspectives are unclear. Conclusions: The American College of Preventive Medicine developed practice recommendations that include encouraging screening for ENDS use, strategies to prevent the initiation of ENDS use in nonsmokers, particularly in youth, adoption of a harm reduction model for smokers intending to quit in those who refuse or fail to quit with evidence-based smoking-cessation methods, recommendations on policy and regulatory strategies to decrease public use of ENDS and regulation of their components, and future research needs.