“In order to close the on-ramp to e-cigarettes for kids, we have to put in place some speed bumps for adults,” Dr. Gottlieb said.

Tobacco companies have fought cutting flavors from e-cigarettes, saying they are not aimed at youths but at adults who need them as a way to transition from tobacco cigarettes. But health advocates point to the packaging and youth appeal of a variety of flavors, including chicken and waffles, rocket Popsicle and unicorn milk as well as fruity tastes like mango.

Dr. Gottlieb has called the attacks on flavored products an “unfortunate trade-off” because they could restrict access to alternatives for adults trying to quit smoking. But, he also said parents should consider their children’s use of e-cigarettes a serious health threat.

“I think that there’s a perception that e-cigarettes are a safer alternative for kids,” he said, “but it can lead to a lifelong addiction, and some percentage will migrate to combustible products.”

The agency’s plans were reported earlier by the Washington Post.

The F.D.A.’s crackdown on flavored e-cigarettes began earlier this year, as the numbers of teenagers vaping reached epidemic proportions and the popularity of such devices soared.