Introduction Flavoured e-liquids are especially appealing to young adults. The objective of the present study was to evaluate the effects of text warning labels (WLs) on e-liquid vials used in flavoured electronic cigarettes (e-cigarettes) on e-cigarette non-users’ perceptions of harm, addictiveness, emotional valence, interest in trying e-cigarettes and visual attention.

Methods Young adults aged 18–25 years (n=313) who were non-e-cigarette users were recruited online and randomised to view images of one of two e-liquid vial conditions (with text WL or without text WL). Each participant was exposed to four images of e-liquid vials. After observing each image, participants reported interest in trying e-cigarettes, emotional valence, perceived harm and addictiveness. Additionally, participants completed an assessment of self-reported visual attention with a priori regions of interest (e-liquid branding and text WL).

Results Separate two-way Analysis of Variance(ANOVA) that examined the main effects of sex and warning were used for each measure. Text WL on e-liquid vials decreased young adults’ intention to use e-cigarettes (especially in men), increased harm perception and decreased appeal to the product. However, they did not influence the perceived addictiveness of e-cigarettes and rarely grabbed attention. Men perceived e-cigarettes as less harmful and less addictive.

Conclusions The results suggest that text WLs on e-liquid vials are moderately effective in preventing e-cigarette use in young adults. However, they capture less attention than the rest of the vial and fail to increase the perception of addictiveness. It is suggested to explore other types of design to increase the effectiveness of WLs.