ABSTRACT: The use of electronic cigarettes (e-cigarettes) is rapidly growing. Recent surveys demonstrate particularly high uptake among young never-smokers and a possible association with increased uptake of combustible cigarette smoking. E-cigarettes may be associated with increased risk of cardiovascular disease, including myocardial infarction, stroke, coronary artery disease, hypertension, and elevated heart rate. However, there is a paucity of long-term clinical data to show the cardiovascular disease implications of these changes. With regard to pulmonary disease, e-cigarettes appear to be strongly implicated in the recent outbreak of acute e-cigarette, or vaping, product use–associated lung injury. The relationship between e-cigarettes and chronic pulmonary disease is less clear, though possible associations with obstructive spirometric changes, chronic obstructive pulmonary disease, asthma, and chronic cough have been demonstrated. Nonetheless, the literature suggests that e-cigarettes are likely less harmful to the cardiovascular and respiratory systems than combustible cigarettes, and emerging evidence suggests that e-cigarettes can be an effective smoking cessation aid for smokers who are motivated to quit.