According to clinical data, the lungs of people who quit smoking can be cleansed after 8-9 months of smoking cessation. The mucosal fibrous tissue of the lungs is cleansed after this period of quitting smoking, and some inflammatory secretions of the lung mucosa caused by lung smoking are gradually discharged from the body by coughing and coughing up sputum. In addition, the immunity of the lungs is improved and the lung function is enhanced, which to a certain extent reduces the possibility of pathogenic infection of the lung tissue. Moreover, the symptoms of withdrawal syndrome, such as coughing, wheezing, shortness of breath, weakness or irritability, which appeared before when quitting smoking, are relieved or even disappear completely.