Millions of Americans use e-cigarettes. Despite their popularity, little is known about their health effects. Some suggest that e-cigarettes likely confer lower risk compared to combustible tobacco cigarettes, because they do not expose users to toxicants produced through combustion. Proponents of e-cigarette use also tout the potential benefits of e-cigarettes as devices that could help combustible tobacco cigarette smokers to quit and thereby reduce tobacco-related health risks. Others are concerned about the exposure to potentially toxic substances contained in e-cigarette emissions, especially in individuals who have never used tobacco products such as youth and young adults. Given their relatively recent introduction, there has been little time for a scientific body of evidence to develop on the health effects of e-cigarettes. Public Health Consequences of E-Cigarettes reviews and critically assesses the state of the emerging evidence about e-cigarettes and health. This report makes recommendations for the improvement of this research and highlights gaps that are a priority for future research. Table of ContentsFront MatterSummarySummary Annex Report Conclusions by Level of Evidence1 Introduction2 Committee ApproachSection I: E-Cigarette Devices, Constituents, and Exposures3 E-Cigarette Devices, Uses, and Exposures4 Nicotine5 Toxicology of E-Cigarette Constituents6 Research Needs: E-Cigarette Devices, Constituents, and ExposuresSection II: Effects of E-Cigarettes on Health7 Modes of Action8 Dependence and Abuse Liability9 Cardiovascular Disease10 Cancers11 Respiratory Diseases12 Oral Diseases13 Developmental and Reproductive Effects14 Injuries and Poisonings15 Research Needs: Effects of E-Cigarettes on HealthSection III: Public Health Implications of E-Cigarettes16 Combustible Tobacco Cigarette Smoking Among Youth and Young Adults17 Smoking Cessation Among Adults18 Harm Reduction19 Modeling of E-Cigarette Use20 Research Needs: Public Health Implications of E-Cigarettes21 Concluding ObservationsAppendix A: Questions from the Center for Tobacco Products of the Food and Drug Administration Submitted for the Committee's ConsiderationAppendix B: Search Strategy and Quality AssessmentAppendix C: Glossary of Terms Related to E-CigarettesAppendix D: Cytotoxicity TablesAppendix E: Public Meeting AgendaAppendix F: Committee Biosketches