The tobacco industry has aggressively marketed menthol tobacco products because they are less harsh and more appealing to youth and other non-users. US law prohibits most flavours in tobacco products but exempts menthol from the ban. In 2020, California enacted a state law prohibiting retail sales of most flavoured tobacco products with ‘characterising flavours’, including menthol. Major tobacco companies vigorously opposed the law and sought its repeal. Despite spending millions of dollars to try to influence the legislature, ballot box and courts, the tobacco industry sought to evade the law by introducing so-called ‘non-menthol’ cigarettes. We describe those industry efforts and California’s responses: California law was amended to redefine illegal flavoured products to include those that create a ‘cooling sensation’ to consumers and established an unflavoured tobacco list making it illegal for retailers to sell flavoured products not on the list. The California experience described in our paper provides a case study demonstrating some best practices that can be replicated by other US states and localities and other countries consistent with the WHO Framework Convention on Tobacco Control.