Science'An uncontrolled experiment'To play this audio please enable JavaScript, and consider upgrading to a web browser that supports HTML5 videoScienceAbbany, Zulfikar05/20/2013May 20, 2013The German Cancer Research Center (DKFZ) says e-cigarettes are unsafe and an 'uncontrolled experiment' on smokers. The DKFZ's Dr Martina Pötschke-Langer tells us how they work and why so many people use them as a means to stop smoking.https://p.dw.com/p/18b5BAdvertisement Interview: Zulfikar Abbany