Quitting smoking is more of a matter of willpower than of individual choice, for smoking is widely recognized as addictive.Although counseling and medication can increase the odds that a smoker quits permanently, the best way to avoid dilemmas is never to take up smoking to begin with. The irreversible effects of cigarette smoking vary in intensity and are related both to the amount and duration of exposure and the age at which the person is initially exposeD、This report challenges the notion that a few years of exposure to smoking will have no lasting harmful consequences.