Electronic cigarettes or "e-cigarettes" (EC) may have a potential public health benefit as a safer alternative to smoking and possibly also as an aid in tobacco dependence treatment. However, there are concerns about their safety and whether they can deliver nicotine consistently and in doses necessary for such effects.

To be able to consider the safety of ECs and their potential in harm reduction, data are needed comparing the exposure to the potential toxicant, acrolein, in smokers of conventional cigarettes, users of EC, and people who use both products at the same time.

To accurately assess EC nicotine delivery, data are needed from people who use them regularly, as there is some evidence of higher and faster nicotine absorption in experienced users compared with naïve users who try them once in an artificial laboratory setting.

This study will provide information on both of these issues. Forty smokers will be given EC to use, in addition to behavioural support, as part of a stop smoking attempt. Levels of acrolein and nicotine will be measured before and after 4 weeks of EC use.

Inclusion Criteria:

• Smokers who want help in quitting
• Aged 18 or over

Exclusion Criteria:

• Women who are pregnant or breastfeeding
• People with any current serious illness

Smokers from the community who wish to stop smoking.