Symptoms such as coughing, phlegm and chest tightness can be significantly relieved or disappear after 90 days of smoking cessation, and lung function may also improve. Regardless of the length of smoking history, quitting smoking is very beneficial to prolonging one’s life. Quitting smoking significantly improves the quality of life and is beneficial to the patient’s own health, reducing the risk of bronchitis, pneumonia, lung cancer, tumors, sudden heart attacks, strokes and chronic lung diseases. Smoke reaches the respiratory tract or the lungs, causing the most common lung symptoms of coughing, sputum and chest tightness, and in severe cases, chronic obstructive pulmonary disease (COPD). These symptoms can be significantly improved or disappear after 3 months of quitting smoking, lung function can be enhanced, circulation can be improved, and lung function can be improved. Smoking is harmful to health and should be stopped as soon as possible.