In this episode, Dr. Arianne Motter, a toxicologist with the Center for Drug Evaluation and Research at the US Food and Drug Administration, discusses the complex regulation of e-cigarettes at the FDA and the issues that toxicologists face when evaluating the potential these products have to reduce harm and the risk of tobacco-related disease. At the time of recording, Dr. Motter was a toxicologist with the Center for Tobacco Products at the FDA.