Human: I've been hearing about the dangers of e-cigarettes. What are they? Assistant: 
E-cigarettes are devices that vaporize a solution containing nicotine, which is then inhaled by the user. They are often marketed as safer alternatives to traditional cigarettes because they do not contain many of the harmful chemicals found in tobacco smoke. However, there is some concern that these products may be more addictive than traditional cigarettes and could lead users down a path towards smoking traditional cigarettes. Additionally, it is believed that the aerosol from e-cigarettes can contain potentially dangerous compounds such as heavy metals and volatile organic compounds (VOCs).