Reports and statistics issued by the World Health Organization in the year 2008 showed that smoking is one of the factors that lead to some types of cancer in the lung, esophagus, pharynx, mouth, urinary bladder, pancreas, stomach, and a study was recently published in the American Journal (J Natl Cancer Inst). A health team in Ohio, America, where it was conducted on about 150 thousand people with a follow-up for eight years, and the study indicated that there is an increase in the incidence of colon cancer also among smokers than others, and the study also indicated that quitting smoking removes this effect on smokers in advance.