Tobacco is a plant grown for its leaves, which are smoked, chewed, or sniffed for a variety of effects. It is considered an addictive substance because it contains the chemical nicotine. In addition to nicotine, tobacco contains over 19 known cancer-causing chemicals (most are collectively known as "tar") and more than 4,000 other chemicals. These include acetone, ammonia, carbon monoxide, cyanide, methane, propane, and butane. Over 38 million people in the United States have successfully quit smoking. Yet there are still around 50 million Americans who smoke. The majority say they would like to quit. And, while the number of cigarette smokers in the United States has dropped over recent years, the number of smokeless tobacco users has steadily risen. This trend is likely related to the false belief that smokeless tobacco is safe. It is NOT. Smokeless tobacco carries many of the same health risks as cigarettes. Some people who want to stop smoking, but who still crave th...