A recent announcement by the UK’s Medicines and Healthcare Products Regulatory Agency (MHRA),1 that it “seeks to encourage the licensing of electronic cigarettes and other inhaled nicotine-containing products as drugs and aims to support companies to submit marketing authorisation applications for these products,” should be welcomed.

E-cigarettes are electronic nicotine delivery systems: users inhale vapour created by heating liquid containing a humectant (propylene glycol or vegetable glycerine), nicotine, and flavourings. Although no serious commentator describes e-cigarettes as “completely safe,” [...]