The term "cigarette ingredient" refers to the components used in the production of cigarettes. Some of the synonyms for this phrase include cigarette additives, tobacco constituents, smoke components, smoking mixtures, and cigarette components. These substances can vary greatly and can include everything from tobacco leaves, to flavorings, to chemicals that enhance the addictiveness of the product. Many of these ingredients have been linked to serious health problems such as cancer, emphysema, and heart disease. Governments and health organizations around the world have been working to reduce the use of these harmful components and promote healthier alternatives such as electronic cigarettes or nicotine replacement therapy.