People vape with battery-operated devices used to inhale an aerosol, which can contain nicotine, marijuana, flavorings, and other chemicals. In many e-cigarettes, puffing activates the battery-powered heating device, which vaporizes the liquid in the cartridge or reservoir. The person then inhales the resulting aerosol or vapor. Research so far suggests that vaping is less harmful than combustible cigarettes when people who regularly smoke switch to them as a complete replacement, but e-cigarettes can still damage a person’s health. Vaping can lead to nicotine addiction and increased risk for addiction to other drugs. It also exposes the lungs to a variety of chemicals.