What are the causes for Chewing Tobacco
(Smokeless Tobacco)?

Studies have shown that the use of chewing tobacco increases the risk of developing a number of health problems and even potentially fatal conditions; including:
  • cancers of the oral cavity (including cancers of the cheek, gums, lips, tongue, and floor and roof of the mouth);
  • gingivitis and gum disease;
  • tooth decay and loss; and
  • leukoplakia (whitish patches inside the mouth that have the potential to become cancerous)
Some reports show an increased risk for cancer of the esophagus, pancreas, and stomach. Some research studies have shown an association between chewing tobacco use and an increased risk of cardiovascular disease (such as heart attacks and stroke). These risks do not seem to be as great as those of cigarette smokers. Further research is underway to determine whether or not chewing tobacco use presents a significant risk of heart disease and stroke.

Source: http://www.emedicinehealth.com