Quitting smoking. Hand empties a packet of cigarettes into a bin, symbolizing the act of stopping smoking. Giving up smoking is hard as cigarette tobacco contains the addictive nerve stimulant nicotine. Nicotine patches and inhalers have been developed to provide the body with an alternative source of nicotine when stopping smoking. Tar in the tobacco smoke will, over a period of time, stain the skin of a smoker's hand. It produces chronic irritation of the respiratory system and causes lung cancer. Tobacco smoking has also been linked with an increased risk of chronic bronchitis and coronary heart disease.