I say fill cigarette because I use fruit flavored liquids and it helped me develop an aversion to the taste of Tobacco and smoke. A few years ago I had a few drags of a cigarette at a party and it made me want to throw up.

Not saying what I do is harmless, but it's a major harm reduction for me. I went from having some pretty serious lung issues to being able to do intense cardio workouts for several hours without any problems breathing.