Electronic cigarettes will be classified as "medicines" under new proposals to tighten up the regulation of the products.
What are e-cigarettes?
Electronic cigarettes are battery-powered devices that are designed to look and feel like the real thing.
It is estimated that 1.3 million people across the UK use the product, which leaves users inhaling a mist of nicotine instead of smoke.
The process works like this:
When the user sucks on the e-cigarette, liquid nicotine is vapourised and absorbed through the mouth.
When they breathe out, a plume of what appears to be smoke is emitted but it is actually largely water vapour.
Are e-cigarettes safe to use?
However, others have raised concerns about the safety and regulation of the products.
The Medicines and Healthcare products Regulatory Agency (MHRA) found that nicotine levels can be "considerably different" from the level stated on the label and that they cannot be certain about the purity of the nicotine contained inside.
An MHRA spokesman said the amount of nicotine differing from batch to batch casts doubt on how useful the products are to people who want to stop smoking.
So what happens now?
The MHRA will now regulate e-cigarettes so there is a consistent amount of nicotine in all licensed products sold over the counter.
In the long term, it is hoped that all products will be licensed.
Can e-cigarette vapour cause any damage to non-users?
As mentioned earlier, when users exhale from e-cigarettes they produce a white smoke-like vapour which consists largely of water.
The dangers of secondhand exposure is likely to be limited to throat irritation, making e-cigarettes less of a danger than the real thing to non-users.
A report on e-cigarettes by Action on Smoking and Health (ASH) said they are "preferable in situations where secondhand exposure poses serious health risks to others."
Is there anything else I need to know about e-cigarettes?
There are four areas that e-cigarettes are said to have helped smokers, according to ASH.
60% said the products helped satisfy their desire to smoke.
55% said it helped them cut down on cigarettes.
51% said e-cigarettes helped them quit smoking entirely.
51% said it helped eradicate the smell of stale smoke.
The amount of e-cigarette users in the UK has increased over the past three years, with 3% of smokers using them in 2010, 7% in 2011 and 11% in 2013, according to ASH.
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