Gottlieb is talking about reneging on the FDA's four-year extension of the deadline for seeking regulatory approval to continue selling e-cigarettes, which would wreak havoc with a market that he concedes has great potential for reducing smoking-related disease and death. Short of that, he suggests the FDA might force companies to stop offering e-liquid flavors that appeal to minors, even though many smokers who use e-cigarettes to quit say flavor variety is an important part of that process.