Coughing and spitting smelly green sputum may be caused by pneumonia, bronchiectasis or sinusitis. 1. Pneumonia: Lung infections caused by bacterial infections such as Pseudomonas aeruginosa or anaerobic bacteria can cause patients to cough, cough up sputum, sputum as smelly green sputum and other symptoms, which can be accompanied by chest pain, dyspnea and other symptoms. 2. Bronchial dilatation: If patients have a history of recurrent respiratory infections, it will lead to thickening and distortion of the bronchial walls, resulting in bronchial dilatation. Patients with bronchiectasis are often susceptible to Pseudomonas aeruginosa and anaerobic infections, leading to recurrent coughing, sputum, coughing up foul-smelling green sputum and other symptoms. 3. Sinusitis: Bacterial infection of the sinus area leads to secretion of purulent secretions from the mucous membrane of the sinuses, which can also cause coughing and coughing up foul-smelling green sputum and other symptoms. Coughing and coughing up foul-smelling green phlegm can also be caused by other diseases. If the symptoms are not relieved or worsened, it is recommended to consult a doctor in time to clarify the cause of the disease and standardize the treatment under the guidance of the doctor.