Smoking can stimulate the respiratory tract, cause fine bronchial constriction, weaken the ability of the cilia in the trachea to remove mucus, cause sputum stagnation, and affect the sputum discharge after surgery. Open-chest (including thoracoscopic surgery) surgery itself, especially intraoperative side lung is atrophied and non-ventilated, plus the rubbing injury during surgery, is a kind of damage to healthy lung tissue. If the sputum is not adequately drained after surgery, it is very easy to develop pulmonary atelectasis and the chance of lung infection is significantly increased. Theoretically, thoracic patients should be required to quit smoking for at least 2-4 weeks prior to surgery; in practice it is difficult to wait 2-4 weeks before treatment, so long-term smokers are cautioned by their physicians to stop smoking immediately. Smoking patients should keep in mind that a day sooner they quit smoking, the smoother their postoperative recovery will be.