Electronic cigarettes (e-cigarettes or e-cigs) have recently become a popular alternative to conventional cigarettes. Numerically speaking, there are now over 250 different e-cigarette brands that are being marketed as smoking cessation devices. There is not yet sufficient research on their long-term safety but there is great support for the opinion that e-cigarettes are approximately 95% safer than smoking. Its effectiveness might partly be explained by the fact that e-cigs satiate both the addiction to nicotine and the behavioural aspect of smoking such as the actual hand-to-mouth movements.

E-cigs were invented and popularized by pharmacist Hon Lik in 2003. These devices have been designed to deliver nicotine with chemicals such as flavourings to users in the form of vapour. They are electrically operated using a lithium battery and their designs can be varied to emulate traditional tobacco cigarettes, cigar pipes, or even pens or USB memory sticks. RELX electronic cigarettes generally contain nicotine, a type of flavouring (molasses and fruit are common) and propylene glycol - a manufactured liquid used in food, cosmetics, and certain medicines to absorb water and help them retain moisture.

These e-cigs function by using a small, heated coil (atomizer) to vaporize a cartridge of liquid solution (usually containing a decided concentration of nicotine) into an aerosol mist. Users inhale the mist just as they would the smoke of an ordinary cigarette but they are not exposed to tobacco, which turns into carcinogenic tar when burned. E-cigarettes are very often promoted as safer alternatives to traditional cigarettes, which deliver nicotine by burning tobacco. Whilst these claims could very well be true, there is still much to be learned about the health risks of using these devices.