The days of menthol cigarettes and strawberry-flavored e-cigs may be numbered.

The Food and Drug Administration is taking the first step toward implementing a rule about the role that flavors, including menthol, play in attracting users to certain tobacco products. On one hand, fun e-cig flavors like creme brulee might be enticing teenagers and young adults, but the FDA is trying to balance that with the flavors helping some adults to quit smoking traditional cigarettes.

The agency is considering banning or restricting menthol and other flavors from tobacco products. One of the questions it's seeking comment on is which types of products should fall under the rule: traditional combustible cigarettes, alternatives like e-cigarettes, or both.

"No child should use any tobacco products, including e-cigarette," FDA Commissioner Scott Gottlieb said, in a statement. "At the same time, we're aware that certain flavors may help currently addicted adult smokers switch to potentially less harmful forms of nicotine-containing tobacco products."

The FDA will also weigh the idea of restricting advertising and promotion of flavored products. It does not currently impose any such rules on e-cigarettes, whereas heavy regulations are imposed on traditional cigarettes.

Flavored products may also be required to offer warnings or disclosure statements on labels and packaging. The only warning statement e-cigarettes are currently required to include is one that states the product contains nicotine and that it's an addictive chemical.

The FDA banned certain flavors in cigarettes in 2009, but menthol was excluded from those new rules, as were other tobacco products. E-cigarettes have come under fire for their fruity flavors serving as a gateway for kids.

The controversy has heightened within the past year as JUUL, a popular e-cigarette, has become popular among adolescents and teenagers. Local news reports document kids bringing the devices, which look like USB drives, to school.

A JUUL spokeswoman did not immediately respond to CNBC's request for comment, but the company has told CNBC in the past that it's ramping up enforcement efforts in response to adolescents using its products.

The FDA, under Gottlieb, adopted the idea that tobacco products exist on a continuum of risk, with cigarettes being the most deadly on the spectrum and e-cigs being seen as potentially less risky.

"The thought of any child starting down a path of a lifelong addiction to tobacco, which could ultimately lead to their death, is unacceptable," Gottlieb said, in a statement. "We need to take every effort to prevent kids from getting hooked on nicotine."

This is the latest action from the FDA, which introduced a sweeping tobacco initiative over the summer. Last week, the agency took the first step toward lowering the level of nicotine in cigarettes to minimally addictive or nonaddictive levels.

Tobacco companies have said they welcome the FDA's approach. Menthol, however, may be prove to be more contentious. Spokespeople for Altria and Philip Morris International did not immediately respond to CNBC's request for comment.

Reynolds, which was acquired by British American Tobacco last year, has poured money into fighting a ban on flavored tobacco in San Francisco. It makes Newport, the most popular menthol cigarette and the second most popular cigarette, representing about 14 percent of the overall market in 2016, according to Euromonitor International.

Reynolds also makes the next two best-selling brands: Camel and Pall Mall, both of which offer menthol variations.

"We support responsible approaches to regulating flavors and balancing the growing evidence that flavors play an important role in helping adult smokers switch to alternatives that potentially present less risk than cigarettes," Dr. James Figlar, executive vice president of RAI Services Company, an indirect subsidiary of Reynolds American Inc., and executive vice president of research and development for R.J. Reynolds Tobacco Company, said in a statement.

The FDA's public comment period will be open for 90 days.