Question: Were statewide restrictions on flavored e-cigarette sales in Massachusetts, New York, Rhode Island, and Washington associated with a reduction in total e-cigarette unit sales from 2014 to 2020?

Findings: In this cross-sectional study, a difference-in-differences analysis of e-cigarette retail data showed that statewide restrictions on non–tobacco-flavored e-cigarette sales were associated with reductions of 25.01% to 31.26% in total e-cigarette unit sales compared with total sales in states without restrictions. The reductions were attributable mostly to decreases in non–tobacco-flavored e-cigarette sales.

Meaning: In this study, statewide restrictions on sales of non–tobacco-flavored e-cigarettes were associated with reductions in e-cigarette sales.