The addictive property of tobacco is due to one of its component alkaloids,nicotine. Raw and processed tobacco has been shown to contain over 2500 different chemical constituents. Tobacco contains a variety of different chemical of these constituents ,tobacco specific N-nitrosa are the compounds which are thought to be the major Carcinogenic agents in tobacco. Other nitresamines are also found in the processed tobacco. Tobbaco chewing and tobacco snuff uasage generally described as smokeless tobacco.
Tobacco is smoked in one of the three basic ways.
The earlier forms of cigarette probably comprised shredded,crudely cured tobacco wrapped in vegetable or other plant leaves or shredded tobacco tamped inside a hollow piece of reed or bamboo. An example of this basic form of cigarette is the Indian bidi. A bidi consists of a small quantity of shredded,sun-cured tobacco which is hand rolled into a piece of tendu. These bidis are very popular in the Indian subcontinent. Smoking of bidis may commence at a very early age.