Well, I will start this reply with a bummer. I quit smoking on Aug. 2 after 30 + years. On Nov. 4th, I was diagnosed with small cell lung cancer. I just finished my first round of chemo this afternoon. I am still vaping -it's kind of like, why the hell not, at this point. I almost guarantee that, if it weren't for Ecigarettes, I probably would have returned to smoking on getting the bad news. Anyway, yesterday I met with the radiation oncologist, and shared with him that I was vaping, and asked his opinion. He was quite blunt, and said the usual party line, they haven't been out long enough to truly know how harmful they may be or not be. But then he shared his opinion, that, from what he has studied over the years, he can see no evidence that nicotine, by itself, has any carcinogenic properties. He then added that, if it keeps me from smoking analogs, he has no problem with it. Just his two cents worth.