E-cigarettes: Safe to recommend to patients?

Electronic cigarettes (e-cigarettes)--devices that generate a nicotine vapor that can be inhaled by the user in a fashion that mimics the experience of smoking--are increasing in popularity, and many people seem to view them as reasonable alternatives to nicotine replacement therapy to help them refrain from smoking. Physicians should not encourage such a view. E-cigarettes are unregulated nicotine delivery systems that have never been subjected to any kind of testing of safety or of efficacy as nicotine replacement therapy. Moreover, for young people who have never smoked, these devices could potentially serve as a gateway drug.