Brain

Nicotine stimulates the brain's reward system, producing feelings of pleasure which lead to addiction.

Mouth and Throat

The tar in cigarette smoke can cause cancer in the tissues of the mouth and throat as well as the lungs.

Facial Skin

Carbon monoxide decreases the ability of blood to carry oxygen to tissues, including skin. The result is a graying of the skin and more wrinkles. The skin does not heal as quickly or as well after surgery. Many cosmetic sergeons urge their patients to stop smoking, especially before procedures and during the healing process.

Esophagus

Cigarette smoke and the juice from smokeless tobacco products often escape into the esophagus, the passageway that leads to the digestive system. This puts the entire digestive system at risk for cancer.

Lungs

A smoker is 15 times more likely to develop lung cancer than a non-smoker. In addition, a smoker's lungs become chronically inflamed and more likely to develop infections such as bronchitis.

Heart and Arteries

Heavy smokers are more likely than others to die from a heart attack. Nicotine makes high blood pressure worse, and it encourages hardening of the arteries, which causes heart disease.