All of these posts have raised good points. And I am not cutting down PG by any means, but I had to quit using it and went to non-PG, or Vegetable Glycerin....my throat would get very sore, and after a time I was developing a quite severe hoarseness that didn't go away, so changed to VG exclusively. So far (in about 2-3 weeks) have not had a hoarse recurrence. To test the theory, I went back to PG for one day, hoarseness came back! And I cannot really tell the difference between the two, except that maybe with VG I felt like I had to brush my teeth more often. Not really a "greasy" feel, something like that though. Difference between the two may also be that PG is a little more drying to mouth and throat tissue, possible lung tissue, depending on how you inhale. I am a quite heavy vaper also. But neither one is harmful, to my research. Both are germicides, when vaporized. The claim of being anti-viral, I am not sure about that, anyone have data on that?