Cancer is defined as the unwanted growth of cells in any part of the body. There are various reasons that lead to development of cancerous growths in the body. There can be various reasons that lead to cancerous growths in the body. Genetic predisposition and environmental factors together play an important role. Genetic constitution of the body is something that cannot be dealt with. But controlling the external environmental factors is in one’s hands. Active or passive smoking is one of the biggest causes that results in development of various cancers in the body. In a health study it has been evidently shown that about 30% of the deaths due to lung cancers were those of who either smoke actively or are exposed to passive smoking. This data is proof enough to describe the serious complications of smoking. Besides, it is not just the lung tissue that is affected by smoking. Carcinoma of oral cavity, pharynx, larynx, kidney, pancreas and other systemic organs of the body are evident. More than 6000 substances are released during smoking. Out of which 70 chemicals are known to act as carcinogens. These chemicals settle down in the lining of air ways and adversely affect the basic unit of respiration- the alveoli. Tobacco which is the main ingredient of smoking also leads to carcinoma of the oral cavity. The internal mucosa is severely damaged and continuous exposure leads to irreparable damage. A smoker is four times at a higher risk of developing mouth cancer as compared to non-smoker. The commonly affected areas are beneath the tongue and lips in the oral cavity. The vital organs of the body like liver, kidney, pancreas, colon and rectum also develop the risk of development of carcinomatous growth. Women who smoke also suffer a chance of developing breast cancer besides the above stated types. Higher incidences of cervical cancer have been noticed in women who smoke. According to researchers, 1 out 5 heavy smokers will die of lung cancer. The ratio for moderate smokers declines to 1 in 10 persons. Another alarming case is that among all the lung cancer patients only 0.5% persons are non-smokers. The rest of the cases had a history of smoking. Lung cancer is one of the commonest types of cancer that lead to death in maximum number of patients throughout the world. In the advanced stage of disease other distant organs of the body are also affected and result in severe complications. Eventually the whole physiological system of the body collapses. Besides cancer smoking leads to various other grave medical diseases. Affecting the functioning of heart, viz. Coronary thrombosis; affecting the eye sight and predisposition to cataracts and macular degeneration and eventually vision loss; and brain in cases like cerebral thrombosis; smoking poses a threat to the whole physiological system of the body. Cancer is defined as the unwanted growth of cells in any part of the body. There are various reasons that lead to development of cancerous growths in the body. There can be various reasons that lead to cancerous growths in the body. Genetic predisposition and environmental factors together play an important role. Genetic constitution of the body is something that cannot be dealt with. But controlling the external environmental factors is in one’s hands. Active or passive smoking is one of the biggest causes that results in development of various cancers in the body. In a health study it has been evidently shown that about 30% of the deaths due to lung cancers were those of who either smoke actively or are exposed to passive smoking. This data is proof enough to describe the serious complications of smoking. Besides, it is not just the lung tissue that is affected by smoking. Carcinoma of oral cavity, pharynx, larynx, kidney, pancreas and other systemic organs of the body are evident. More than 6000 substances are released during smoking. Out of which 70 chemicals are known to act as carcinogens. These chemicals settle down in the lining