Coughing without cold symptoms is considered to be an inflammation of the tracheal and bronchial mucosa, caused by exposure to cold air, dust or irritating gases, and may also be caused by an allergic reaction due to inhalation of allergens. For bronchitis, dextromethorphan and pentoxifylline can be used to stop coughing if there is no obvious coughing up of sputum. In addition, if the cough is more than 10 days old, it is likely to be accompanied by a bacterial infection and should be treated with antibiotics, preferably macrolides or penicillins. During treatment, rest, drink plenty of water and avoid straining.