Starting at the Top
As a smoker, you're at risk for cancer of the mouth. Tobacco smoke can also cause gum disease, tooth decay and bad breath. The teeth become unsightly and yellow. Smokers may experience frequent headaches. And lack of oxygen and narrowed blood vessels to the brain can lead to strokes.
Lungs and Bronchi
Moving down to your chest, smoke passes through the bronchi, or breathing tubes. Hydrogen cyanide and other chemicals in the smoke attack the lining of the bronchi, inflaming them and causing that chronic smoker's cough. Because the bronchi are weakened, you're more likely to get bronchial infections. Mucus secretion in your lungs is impaired, also leading to chronic coughing. Smokers are 10 times as likely to get lung cancer and emphysema as nonsmokers.