BackgroundKnowledge about the health effects of e-cigarette use (or vaping) among past and current combustible cigarette users is limited. Several studies have assessed vaping-related adverse events (AEs) and beneficial health effects, however, most studies focused on AEs in general and examined only a few physiological changes that vapers experience. This study aims to explore self-reported AEs and perceived health changes due to e-cigarette use among Hungarian adult e-cigarette-only users (former smokers who switched completely to e-cigarette use) and dual users (smokers who use e-cigarettes and combustible tobacco cigarettes concomitantly).MethodsA cross-sectional, web-based survey of 1042 adult Hungarian e-cigarette users was conducted in 2015. Participants reported AEs and changes in physiological functions since they switched from smoking to e-cigarette use or while dually using e-cigarettes and combustible cigarettes. Confirmatory factor analysis with covariates was applied to explain perceived health changes due to e-cigarette-only use and dual use.ResultsDual users (17.6%) were significantly more likely to report AEs of vaping than e-cigarette-only users (26.2% vs. 11.8%, p < 0.001). Experiencing health improvements were significantly more likely among e-cigarette-only users than for dual users for all surveyed physiological functions. E-cigarette-only users reported larger effects of vaping on sensory, physical functioning, and mental health factors compared to dual users. Self-reported changes in sensory and physical functioning were significantly higher among individuals using e-cigarettes more than a year and people who were past heavy smokers (smoked ≥20 cigarettes per day). Gender was related to sensory improvement only; males reported greater improvement than females.ConclusionsThe majority of e-cigarette-only users reported more perceived beneficial changes in physiological functions and fewer AEs than dual users. Perceived short-term benefits of e-cigarette use may reinforce users despite the uncertainty of long-term health consequences. Health professionals should provide balanced information regarding the possible short- and long-term positive and negative health effects of e-cigarette use during consultations with patients.Electronic supplementary materialThe online version of this article (10.1186/s12889-019-6629-0) contains supplementary material, which is available to authorized users.