Objectives To provide the policy-relevant estimates of impacts of alternative flavour bans on preferences and demand for cigarettes and e-cigarettes in adult smokers and recent quitters.

Methods A best–best discrete choice experiment (DCE) is used to elicit smokers’ and recent quitters’ preferences for flavours, price, health impact and nicotine level in cigarettes and e-cigarettes. Choice of tobacco products and an opt-out option were examined. An efficient design yielded 36 choice sets. Exploded logit choice models were estimated. Flavour bans are modelled by restricting flavour coefficients in the estimated model.

Setting and participants A sample of 2031 adult smokers and recent quitters was recruited to complete an online survey and DCE.

Results Current smokers and recent quitters, on average, prefer cigarettes and menthol cigarettes over flavoured e-cigarettes. However, there is substantial preference heterogeneity by younger adults (ages 18–25), race/ethnicity and respondents with higher education. Our predictions suggest that a ban on menthol cigarettes would produce the greatest reduction in the choice of cigarettes (−5.2%), but with an accompanying increase in e-cigarettes use (3.8%). In contrast, banning flavours in e-cigarettes, while allowing menthol in cigarettes would result in the greatest increase in the selection of cigarettes (8.3%), and a decline in the use of e-cigarettes (−11.1%). A ban on all flavours, but tobacco in both products would increase ‘opting-out’ the most (5.2%) but would also increase choice of cigarettes (2.7%) and decrease choice of e-cigarettes (−7.9%).

Conclusions A ban on flavoured e-cigarettes alone would likely increase the choice of cigarettes in smokers, arguably the more harmful way of obtaining nicotine, whereas a ban on menthol cigarettes alone would likely be more effective in reducing the choice of cigarettes. A ban on all flavours in both products would likely reduce the smoking/vaping rates, but the use of cigarettes would be higher than in the status quo. Policy-makers should use these results to guide the choice of flavour bans in light of their stance on the potential health impacts both products.