Smoking is one of the leading preventable causes of health disorders, including illnesses of the digestive tract. Tobacco contains many toxins that are harmful to the body. Smoking contributes to the development of heartburn and peptic ulcers, impairs the liver and may increase the risk of Crohn's disease.

Smoking can also cause cancers of the digestive tract, such as cancer of the mouth, throat or esophagus. Some research indicates that smoking may raise the risk of colorectal cancer. It can also contribute to health disturbances in the digestive tract that are less serious, but nonetheless bothersome. Air swallowed during smoking can increase the likelihood of belching, flatulence or bloating due to the extra air in the body. Smokeless tobacco can also cause these symptoms.

In addition to triggering illnesses of the digestive tract, smoking also causes a variety of potentially life-threatening disorders. These include lung cancer, emphysema (a chronic lung disease) and heart disease.