Effects Tobacco contains nicotine, a drug that acts on the brain and rapidly produces addiction. Scientists estimate that 90 percent to 95 percent of tobacco users are addicted. Its most destructive property is its ability to addict users rapidly. Once addicted, smokers repeatedly expose their brains and bodies to hundreds of toxic chemicals contained in tobacco and tobacco smoke. The list of cancers that tobacco causes is impressive, from cancers of the mouth, head and neck to cancers involving most of the vital organs.
Smoking also causes heart disease, emphysema, and other lung diseases.
Moreover, cigarette smoke can also harm nonsmokers. Children whose parents smoke suffer higher rates of bronchitis and other lung infections, and nonsmoking spouses of smokers have higher rates of lung cancer than those whose spouses do not smoke. Every year, tobacco kills more than 400,000 Americans. This is more deaths than all Americans killed in World War I, World War II, and the Korean and Vietnam wars combined. The industry recruits teenagers to replace those losses.