Smoking refers to the practice of inhaling smoke from the burning tobacco in a pipe, cigar, or most commonly, a cigarette. Smokers feel relaxation because tobacco contains nicotine that is very addictive to a person who smokes. Smoking causes numerous hazards, which include: cancers, second hand smoke problems, and problems in pregnancy. “Cancers of the lung, breast, prostate and colon and rectum have become more frequent in countries with risk factors such as cigarette smoking.” More than half of the cancer deaths in the United States can be attributed to tobacco smoke. Smoking causes 30 percent of cancer deaths in the U.S. . “Smoking mainly of cigarettes causes cancer of the lung, upper respiratory tract, esophagus, bladder and pancreas and probably of stomach, liver and kidney”. Smoking is linked in leukemia and may also cause cancer of the colon and rectum and other organs.