Professor Sir Chris Whitty warned that more must be done to stop children vaping and said it's "utterly unacceptable" that products are being marketed toward kids.
England's Chief Medical Officer voiced alarm over disposable vapes such as Elf Bars, saying officials must look "seriously" at the problem.
He made the remarks after being asked about vaping becoming a "fad" among teenagers.
Sir Chris told MPs on the Health and Social Care Select Committee that a rise of vaping among children is an "appalling situation".
He said: "Is it reasonable to have, in any case, flavours and colours that are clearly aimed at essentially encouraging people to vape who may well not be vaping at all?
"Because absolutely much rather people don't vape at all than not, it's only those who already smoking where vaping is the route out for them, where vaping has a clear public health goal.
"I think we need to be much more serious, in my view, that trying everything we can to reduce vaping in children, as well as smoking in children, is really important whilst trying what we can do to make sure that vaping is available for those for whom that is the root out of smoking.
"So it's getting that balance right. And there's quite a lot of debate around the world how to do this."
He added: "Disposables vapes are clearly - things like Elf Bar - are clearly the kinds of products which look as if they're being marketed, in reality, at children.
"And I think we should look very seriously at these products for which the child market appears to be the principal market and say 'why are we considering this to be a good thing to have'?"
The remarks came after Tory MP Dr Caroline Johnson, MP said: "We know it is not as good for you as breathing fresh air, and one of my concerns is that something which was supposed to be a stop smoking device, like nicotine gum, has become a fad, heavily marketed at children, which is developing in a whole generation of teenagers completely addicted to sucking little nicotine coloured pop things.
"What are your thoughts on the effects on the teenagers health of vaping and how do we stop them from getting addicted?"
Sir Chris replied: "Everyone agrees I think that it is far safer for someone to vape than to smoke. So if the choice has to be between one of two of those - they're smoking heavily now, they want to come off smoking, and they can move on to vaping, they can't just completely stop, then that is a net benefit in health terms.
"And vaping has an important role as a public health tool to help smokers who are addicted to often no choice of their own at this stage to come off smoking. So I think I think everyone agrees with that.
"I think everyone agrees that marketing vaping, an addictive product, with, as you imply, unknown consequences for developing minds, to children is utterly unacceptable. Yet it is happening.
"There's no doubt it's happening because, although from a low base, the rates of vaping have doubled in the last couple of years among children. So that is an appalling situation."
