For thousands of years, people have smoked or chewed the leaves of the tobacco plant, Nicotiana tabacum. Tobacco was first found and cultivated in the Americas, perhaps as early as 6000 B.C. Following the discovery and colonization of North and South America, the tobacco plant was exported widely, to continental Europe and the rest of the civilized world. Even in its early days, tobacco use was controversial. Some hailed its medicinal properties. For example, tobacco was supposed to be protective against the ravages of the Plague. As early as the 1600s, people speculated that there might be a link between diseases, like cancer, and tobacco use. Since then, modern research methods have provided evidence of this link, and public service announcements that warn of tobacco's health risks and addictive nature are seen regularly on TV.
What is it about tobacco that makes people so compelled to use it despite all of the admonitions? Smoking or chewing tobacco makes people feel good, even mildly euphoric. While there are thousands of chemicals in the tobacco plant (not to mention those added by cigarette manufacturers), one, nicotine, produces all the good feelings that draw people back for another cigarette or plug of tobacco. In this article, we'll examine nicotine and how it affects the human body.