Vaping
An e-cigarette is a plastic electric cigarette with a heating element. It holds a nicotine cartridge containing liquid nicotine which, when heated, changes the nicotine into a vapour. The nicotine and other ingredients are inhaled into the body.
E-cigarettes are a comparatively new and rapidly evolving product. Many people are using e-cigarettes (also known as vaping) as an alternative to smoking tobacco. Research into the safety and effectiveness of e-cigarettes is still relatively new.
Because they're similar in shape and appearance to cigarettes, e-cigarettes can be helpful for people used to holding a cigarette.
Safety
Although e-cigarettes are almost certainly significantly less harmful than smoking tobacco, they aren't risk free. Most e-cigarettes contain nicotine, which is highly addictive, as well as other ingredients such as propylene glycol, glycerine and flavourings.
E-cigarettes have been regulated by the government since May 2016. From April 2017 it's illegal to sell e-cigarettes to, or buy them for, under 18s.
If you use e-cigarettes as a complete replacement for smoking, you'll almost certainly benefit your health. The health benefit comes from stopping smoking, not using an e-cigarette. It will be some time until studies will show the long-term impact and any unforeseen risks of using e-cigarettes. More is known about the safety and effectiveness of other stop smoking medications.
Alternatives
E-cigarettes aren't the only option for smokers looking to stop. If you're looking to quit you could consider using proven methods of stopping smoking such as Champix, nicotine replacement therapy (NRT) or Zyban to help to break your reliance on nicotine.
If you miss the routine of holding a cigarette, you could consider an NRT inhalator. This looks like an e-cigarette.