Dr. Guadalupe Ponciano Rodríguez, a specialist in addiction and its treatment, said many brands of electronic cigarettes contain nicotine, and many users do not know what they are "smoking."
"That smoke really is not water vapor," he said. "Manufacturers include propylene glycol and diethylene glycol, which are highly irritating types of alcohol."
What I forgot to mention the Dr is what are the effects of these components in our body. See it here in this article Electronic Cigarettes, Diethylene Glycol or Propylene Glycol. Cancer?
Rodríguez added that other treatments are much more effective in getting smokers to quit as "patches of nicotine, inhalers and chewing gum."