Nicotine has been used as a commercial insecticide and fumigant, and the news doesn't get better. Each year, 440,000 cigarette smokers die, and for every one death caused by a smoking-related disease there are 20 more people living with at least one serious smoking-related illness [source: CDC]. Tobacco use of any kind comes with numerous health risks. Tobacco smoke contains at least 250 chemicals known to be toxic or to cause cancer. A smoking habit of just one to four cigarettes a day is enough to increase your chance of developing cardiovascular disease. Pneumonia, emphysema and respiratory infections, cataracts and eye problems, and certain cancers including cancers of the mouth, pharynx, larynx, esophagus, stomach, pancreas, cervix, kidney, ureter and bladder as well as some leukemias are all known risks of a nicotine addiction. The risk of dying from cancer -- lung or another type -- doubles if you're a smoker, and as many as nine out of 10 people diagnosed with lung cancer can directly blame their tobacco habits [source: MedicineNet, MayoClinic].
Smokers are also more likely to suffer from periodontal disease, diabetes (or insulin resistance), infertility and pregnancy complications, and changes in their physical appearance (including premature aging and yellow-stained, sallow skin). On average, nonsmokers live about a decade longer than smokers [source: CDC].
Despite its dark side, nicotine hasn't always been vilified; Native Americans, for example, smoked tobacco not only for ceremonial reasons but also considered it to have medicinal properties. And it may. Today's research finds there may be some positive uses for nicotine through safer delivery methods than cigarettes, including evidence that it may reduce the risk of developing Parkinson's disease and Alzheimer's disease. It may also show promise as a treatment for depression, anxiety and schizophrenia, and could possibly even help with wound healing [source: Graham, Leary].