Smoking, one of the avoidable causes of mortality, is considered a major risk factor for cardiovascular diseases, chronic obstructive pulmonary diseases, and bronchopulmonary cancer. Many studies suggest that nicotine induces vasoconstriction, not only in coronary arteries but also in peripheral vessels, hypertension, pro-atherogenic effects, due to increase of platelet activation and fatty acids concentration, alterations of endothelial-cell shapes, as well as endothelial-cell proliferation. The main affected vascular biochemical parameters are: endothelin-1, cholesterol, triglycerides, lipoproteins, C-reactive protein, nitric oxide, fibrinogen, and uric acid. Cigarette smoke induces inflammation in respiratory epithelium, through local irritation due to release of oxidants, aldehydes, acids, ammonium; impaired ciliar function, and retention of mucus and toxins, followed by infection; carcinogenesis due to oncogene-expression induced by oxidants, aromatic hydrocarbons, and nitrosamines. These effects are induced by alterations of endothelin-1, nitric oxide, IL1, IL6, TNF, and the CYP Enzyme System. Saliva is the first biological fluid encountered by the cigarette smoke. In vitro and in vivo salivary exposure to cigarette smoke has been shown to determine changes of concentrations of lactate dehydrogenase, amylase, and uric acid, in saliva--important factors of the antioxidant salivary system. Such changes may promote occurrence of upper digestive cancers.