Smoking and gut.

Smoking has not only enormous deleterious effects on cardiovascular, cerebral, and bronchial organs but also profoundly alters the function of all parts of the gastrointestinal tract through various mechanisms. Except the sole curiously observed benefit of smoking on the course of ulcerative colitis, it increases the prevalence of the common gastrointestinal diseases namely gastroesophageal acid reflux, peptic ulcer, and Crohn's diseases. It also increases the incidence of cancer of oral cavity, esophagus, stomach, pancreas, and liver mostly in a dose-response relationship and worsens the prognosis of colon cancer. The cessation of smoking is associated with the reduced incidence of cancer in the reported organs, but its effect on the regression of benign disease is not generally studied. The physicians must be aware not only of the harmful effect of smoking on the cardiovascular and bronchial systems, but also about the detrimental consequences of life-long smoking on the gastrointestinal tract and the increase of its benign and malignant diseases.