Nicotine has come a long way from the glamorous depictions of smoking in the movies and advertisements of the early- to mid-20th century. It is now recognized for what it really is, a killer of millions of Americans through cancers, lung diseases, and heart disease. Smoking is the leading preventable cause of death in this country. However, be encouraged. Even a person who has used nicotine products for many years can reverse much of the damage by abstaining from use of these addictive substances and engaging in healthy lifestyle habits.