Some adolescents who otherwise would never have smoked are using e-cigarettes, according to a study published July 11 in the journal Pediatrics. The findings suggest that adolescents are not just using e-cigarettes as a substitute for conventional cigarettes but that e-cigarettes are attracting new users to tobacco products. E-cigarettes are electronic devices that create an aerosol by heating a liquid solution that often contains nicotine and flavorings, as well as other chemicals. They allow users to simulate smoking conventional cigarettes by inhaling the aerosol, which mimics combustible cigarette smoking. The Food and Drug Administration recently finalized a rule extending its regulation of tobacco products to include e-cigarettes. The rule went into effect this week.