For patients with pneumothorax, it is advised to strictly quit smoking, as smoking greatly increases the recurrence of pneumothorax. Smoking leads to airway inflammation and respiratory bronchitis. Among male patients with pneumothorax, compared to non-smokers, smokers have a significantly higher incidence of pneumothorax, which is related to the degree of smoking. If the patient smokes less than half a pack, the recurrence rate of his pneumothorax is about 7 times higher. For moderate smokers, those who smoke between half a pack and one pack, the recurrence rate increases to 21 times. If one smokes a pack a day, the recurrence rate rises to 102 times, this is in males. In females, for those smoking less than half a pack, between half a pack and one pack, and more than one pack, the recurrence rates of pneumothorax become 4 times, 14 times, and 68 times respectively. Therefore, for both male and female patients with pneumothorax, smoking significantly increases the probability of recurrence. So, once pneumothorax is resolved, quit smoking as well, to prevent any future recurrences.