I'm a non smoker, I never smoked. Once I decided to try a nicotine chewing gum, took one pillow and chewed it thoroughly. After about 5-10minutes I suffered some very very severe effects, including: I started sweating extremelly such that all my clothes become wet quickly and sweat was dripping down my nose, ears, and into my eyes. I felt an intense and urgent need to urinate and defecate, which luckily I could do on the spot (happened to be in the proximity of a public toilet). I think after about 30minutes the simptoms subsided. I subjectivelly imagined that I ran the risk of a heart attack there.
So, I'd like to warn any non-smoker that may want to try out nicotine: please start with a very small dose, and only gradually build up; because otherwise it can be dangerous.