nicotine is naturally found in tobacco, but the manufacturers of cigarettes do nothing to attempt to reduce the levels of nicotine. the nicotine comes with the tobacco and cannot really be avoided.
Well would you buy a product that:
a. Gives you multiple types of cancer
b. Rots your teeth and deteriotes your appearence
c. Makes you smell
The answer is obviously no. But everyone has peer pressure or hears that this product can "help" you, so maybe you try it. But no one would keep doing this for fun like, "hey let's go get cancer!!" so the cigarette companies need something to help sell their product. Boom! Nicotine! A highly addictive substance that "relieves" someone after a hard day of work. But really what I'm trying to say is:
Once the tobacco buyers realize the effects of tobbaco on their health, they would stop buying it. Nicotine is added to tobacco to help raise company sales by getting more and more people addicted.
Stay Healthy!! =)
Nicotine is naturally present in tobacco and most members of the nightshade family of plants (which includes many common vegetables such as potatoes, peppers, tomatoes, and eggplant), though it's much more concentrated (by several orders of magnitude) in tobacco.
The word "nicotine" is from the genus of the tobacco plant, Nicotiana tabacum.
Plants in the nightshade family form a variety of alkaloid compounds, including nicotine, capsaicin (the chemical that makes peppers hot), atropine (a medicine used to treat low heart rates, but fatal in large doses).
Nicotine is toxic to most insects (it is even occasionally used as an insecticide), so it gave the tobacco plant an evolutionary advantage. Some variants of tobacco are considered an invasive weed in some places because there are so few things that will attack it.